C harlize Theron knew it wouldn’t be easy to make Bombshell, a movie about sexual harassment at Fox News. After all, when it comes to plotlines, that one’s a tightrope.

Still, Theron didn’t expect that two weeks before the film was supposed to shoot, with A-listers Nicole Kidman and Margot Robbie set to star alongside her, Bombshell would nearly fall apart. “It felt like we had been going at top speed toward something risky and then, all of a sudden, the floor was just dropping from underneath us,” she says.

As one of the producers, she kept the budget to a lean $35m, but Annapurna Pictures still pulled out of making the film last autumn in a move that occurred just months before the company released its pricey political comedy Vice, starring Christian Bale. “It’s a tough pill to swallow when you hear your financier wants to back out,” Theron said, “especially when it’s almost half the cost of something that they’ve already done with a man.”

Though Theron leapt into action to secure last-minute financing and a new distributor, she was still wrestling with private doubts about taking on the lead role of Megyn Kelly, the steely Fox News anchor whose accusations against the channel’s chief executive, Roger Ailes, helped topple him in 2016. Kelly remains a controversial figure with both the left and the right, and playing her would require the same sort of prosthestic-laden physical transformation that Theron had undergone for Aileen Wuornos, her Oscar-winning role in Monster.

But come on, this is Charlize Theron we’re talking about. Do you actually expect the woman behind Mad Max: Fury Road’s Furiosa to shrink from a challenge? “Unless it’s something where I really feel like I’m going to go scare myself – like I’m standing on a ledge and if I fall, it might be brutal and not pretty at all – I don’t really want to do it anymore,” she says, last month in West Hollywood.

Here are edited excerpts from our conversation.

The 40 best films of the decade Show all 40 1 /40 The 40 best films of the decade The 40 best films of the decade 40. Once Upon a Time in Hollywood A helter-skelter ride of a movie, satirical, very witty and showing its director’s immense affection for the B-movie actors, stunt men and hangers on who make up its cast. It’s also a tribute to Sharon Tate (Margot Robbie). Who would have believed that a film set just as the Sixties in LA turned sour could be so uplifting? Geoffrey Macnab Sony/Columbia/Rex The 40 best films of the decade 39. The Master The world isn’t scared enough of Scientology, but perhaps it would be if enough people had seen The Master. Paul Thomas Anderson depicts (a fictionalised version of) the cult as a trap for bruised masculinity. Philip Seymour Hoffman and Joaquin Phoenix contort themselves into primitive creatures of greed and desire. It’s an ugly film, in the very best sense of the word. Clarisse Loughrey Snap Stills/Rex The 40 best films of the decade 38. The Irishman Scorsese summons all his sad captains for one last reunion in his magisterial gangster epic. De Niro, Pesci, Keitel and (newcomer) Pacino are all cast in a film as much about friendship, memory and betrayal as it is about corruption in the Teamster union or Mafia violence. GM Netflix via AP The 40 best films of the decade 37. Inside Out This is Pixar’s boldest and strangest animated feature. It takes us deep inside the mind of its heroine, 11-year-old Riley, where her unconscious is shown as akin to a magical theme park; emotions like Joy and Sadness feature as characters. Director Pete Docter deals with complex subject matter in a lithe and inventive way, and without too many Freudian hang ups. GM Moviestore/Rex The 40 best films of the decade 36. Shoplifters Hirokazu Kore-eda is like the Charles Dickens of contemporary Japanese cinema. He tells melodramatic family stories which would seem mawkish if they weren’t so brilliantly observed. Winner of the Palme D’Or in Cannes, this is one of his very best movies – a heart-tugging story about impoverished members of a makeshift family doing everything they can to survive. GM Thunderbird Releasing The 40 best films of the decade 35. Dogtooth Dogtooth is a grim tale of isolation, incest, cat murder and DIY dentistry. But Yorgos Lanthimos has a hidden superpower up his sleeve: the more off-putting his films, the more you get drawn in. His work breeds curiosity. We want to solve the mystery of these strange worlds and their cold, inscrutable characters. The fact that there are no answers keeps us coming back for more. GM Feelgood Entertainment The 40 best films of the decade 34. Edge of Seventeen Kelly Fremon Craig’s gorgeous if cruelly unrecognised The Edge of Seventeen is deliberately small in plot, with Hailee Steinfeld playing a grumpy teen horrified to discover her best friend is dating her older brother. But it is told with heartwarming urgency, reflective of the heightened, dizzying drama of merely being a teenager. Moviestore/Rex The 40 best films of the decade 33. A Quiet Passion Reclusive New England poet Emily Dickinson, who published only a handful of poems during her lifetime, is brought to life in vivid fashion by actress Cynthia Nixon in Terence Davies’s biopic. She may look like a spinster aunt but Nixon shows us her passion, mischief and her eccentric brilliance. Music Box Films The 40 best films of the decade 32. Frances Ha Noah Baumbach’s Frances Ha is the definitive film about the quarter-life crisis, largely because it embraces the messiness of it all. We get the ups and the downs. We get the poorly-planned trip to Paris made by a young woman desperate to experience something profound. It’s a film without many dramatic conflicts, but marked by a gentle push towards accepting the inevitability of change. IFC Films The 40 best films of the decade 31. The Revenant Famous for its scene of Leonardo Di Caprio being mauled by a bear, Alejandro González Iñárritu’s western is part survival drama, part revenge movie. It’s a wilderness tale on the very grandest scale. From the opening massacre to the snowbound denouement, it if full of moments that startle you with their violence and their beauty. GM 20th Century Fox The 40 best films of the decade 30. Boyhood Shot over 12 years, Richard Linklater’s Boyhood is the ultimate coming-of-age movie. It follows main character Mason (Ellar Coltrane) from when he is seven years old until he is a young adult. It’s a testament to the patience and ingenuity of Linklater and to the exceptional work of his cast (including Patricia Arquette and Ethan Hawke) that the film never feels phoney. GM Sundance Institute The 40 best films of the decade 29. Hereditary The horrors of Ari Aster’s occult contraption are matched only by the sheer volume of ideas crammed into it. A devastating kaleidoscope of stark images, mischievous easter eggs and pure, guttural horror, Hereditary asks a staggering amount of star Toni Collette, who wails and groans and weeps, as if conveying a full-body demolition in painful slow-motion. It is a performance for the ages in one of the best films in recent memory. A24 The 40 best films of the decade 28. Melancholia Kirsten Dunst is remarkable as a bride in the grips of mental illness shortly before the world ends. She conveys like few before her the surging apathy and bottomless self-loathing of depression, where everything, be it food or otherwise, tastes like ashes. The film that surrounds her is equally awe-inducing, distilling with grim elegance all of Lars von Trier’s polarising genius. AW Canal+ The 40 best films of the decade 27. Selma Selma is a masterclass in the historical biopic. Presenting a crucial moment in Martin Luther King Jr’s life without dramatic embellishment or emotional manipulation, it lets his legacy speak for itself, as Ava DuVernay wields her camera like a weapon of truth. Unabashedly political in its approach, Selma speaks plainly to the fact that society cannot pave its future without first understanding its past. CL Paramount/Rex The 40 best films of the decade 26. Boy Taika Waititi’s films always end with the feeling that things will work themselves out. It’s not blind optimism, but something far more comforting – he believes deeply in people’s ability to weather even the worst of storms. This is most apparent in Boy, still his best film to date, which catalogues a young Maori boy’s dawning realisation that his absent father isn’t the hero he imagines him to be. CL Transmission Films The 40 best films of the decade 25. Dunkirk British stoicism and grace under-fire are foregrounded in Christopher Nolan’s epic film about the Dunkirk evacuations. Nolan has a Cecil B De Mille-like genius for orchestrating crowd scenes and working with huge ensemble casts. He combines spectacle with very intimate moments that show the quiet desperation of the soldiers stranded on a French beach with little chance of escape. Warner Bros The 40 best films of the decade 24. Her Her felt almost uncomfortably relevant upon its release in 2013, and even more so today. Not because it shows people falling in love with artificially intelligent operating systems voiced by Scarlett Johansson, which hasn’t exactly caught on (...yet), but for what it said about modern loneliness. It is a sparse, oddly human film, Joaquin Phoenix finding solace and romantic fulfilment in sparkly new technology, before everything falls apart. AW Warner Bros The 40 best films of the decade 23. Call Me by Your Name Luca Guadagnino’s wonderfully evocative coming-of-age drama, set over a long, lazy Italian summer sometime in the 1980s, is notable for its frank but delicately observed account of the love affair between the precocious adolescent Elio (Timothée Chalamet) and the American academic, Oliver (Armie Hammer), who becomes part of the household. GM Warner Bros The 40 best films of the decade 22. Anomalisa It may be animated but few live-action films have captured middle-aged male angst and disillusionment as well as Charlie Kaufman’s Anomalisa. David Thewlis’s exceptional voice work brings an extra, sardonic edge to its portrayal of the businessman on a work trip to Cincinnati. Kaufman captures the man’s vulnerability, boredom and creeping disappointment about the course his life has taken. GM Paramount Pictures The 40 best films of the decade 21. The Social Network Described upon release as a lightly fictionalised account of the birth of Facebook, and as “hurtful” by Mark Zuckerberg himself, The Social Network was always spectacular, but its lessons have only deepened with time. It now resembles a terrifying warning about privacy, power, misogyny and the dangers of the internet, brought to life by David Fincher’s irresistibly cool direction, a characteristically snappy script by Aaron Sorkin and the dreamy, pulsating score by the now-ubiquitous Trent Reznor and Atticus Ross. It remains the most important film of the decade. AW Columbia The 40 best films of the decade 20. Black Swan It’s important to occasionally remind yourself that Black Swan, a bonkers, uncompromising and horrifying ballet thriller, somehow grossed $329m at the box office. But even removed from its staggering financial success, Darren Aronofsky’s psychological creepshow is a creative triumph. Part Showgirls, part Polanski and all Perfect Blue, it flirts with camp, Cronenbergian body horror and shaky-cam intimacy, with the deservedly Oscar-winning Natalie Portman as the twirling, crumbling creature at its centre. AW Moviestore/Shutterstock The 40 best films of the decade 19. Roma Roma takes two stories – one heartwrenching and intimate, the other sweeping and political – and weaves them together so delicately that they become one. It’s a tribute to the domestic worker who director Alfonso Cuarón says raised him. But it’s also the story of Mexico’s history, as seen through the perspective of those who have, for so long, been left voiceless. This is Cuarón’s masterpiece. CL Carlos Somonte The 40 best films of the decade 18. The Act of Killing It feels remarkable, given how easy it is to turn away from evil, that The Act of Killing exists at all. Not only did Joshua Oppenheimer choose one of the perpetrators of the Indonesian genocide as his subject of his documentary, but he had him confront his own crimes through a series of cinematic reenactments. It is profoundly disturbing to watch. CL Dogwoof The 40 best films of the decade 17. Stoker Park Chan-Wook’s twisted homage to Hitchcock’s Shadow of a Doubt may be filled with beautiful things, but they’re laced with venom. When India (Mia Wasikowska) receives a visit from her enigmatic Uncle Charlie, she discovers they share a perverse kinship. Are they the same soul in two different bodies, or are they merely bound together by the stench of death that follows them wherever they go? CL Rex Features The 40 best films of the decade 16. The Selfish Giant Like Ken Loach’s Kes, Clio Barnard’s Bradford-set tale, very loosely inspired by the Oscar Wilde story, combines lyricism with polemic. It captures brilliantly the mischief and resourcefulness of its two young protagonists (teenage kids excluded from school) while laying bare the brutality of the society in which they and their families are cast adrift. GM Rex Features The 40 best films of the decade 15. Son of Saul In 'Son of Saul' Geza Rohrig plays a Hungarian-Jewish prisoner tasked with the extermination of his fellow Jews Sony Pictures Entertainment The 40 best films of the decade 14. Lady Bird Lady Bird – and its story of a frustrated teen (Saoirse Ronan) trapped in Sacramento, California – is deeply attuned to how we relate to memory. It’s less about particular events than the emotions they create: a flash of adolescent alienation, a tearful goodbye at the airport, or the sensation of seeing a familiar place through new eyes. A24 The 40 best films of the decade 13. The Grand Budapest Hotel Wes Anderson’s kitsch yarn, largely set in a luxurious spa hotel just before the Second World War, is an elegy for a lost world. Whether it’s Alexandre Desplat’s music, the eye-popping colours or the mannered but brilliant performances, all the elements here are perfectly judged. A film that could easily have seemed flimsy and conceited is instead utterly enrapturing. GM Moviestore/Rex The 40 best films of the decade 12. 12 Years a Slave Steve McQueen’s harrowing period drama confronts audiences with the reality of slavery. Racist white owners treat their slaves as if they’re livestock, not human beings. Chiwetel Ejiofor excels as Solomon Northup, the free man sold into slavery. The film has a furious polemical charge but also works as a terrifying Kafkaesque drama about a man who falls off the face of the world. GM Lionsgate The 40 best films of the decade 11. Under the Skin Scarlett Johansson tucking nervously into a slice of chocolate cake becomes one of cinema’s most humane and bittersweet moments courtesy of filmmaker Jonathan Glazer, whose once-in-a-blue-moon film projects have produced a trilogy of sinister classics. Like Sexy Beast and Birth before it, Under the Skin is a wild, beautiful pleasure, as haunting as it is tender and serenaded by a spindly, disquieting score by Mica Levi. AW Filmnation/Rex The 40 best films of the decade 10. 20th Century Women 20th Century Women is a small-scale comedy drama with the power of something bigger. A tapestry of restless lives figuring things out, it is about family, longing and feeling out of place. At its heart is Annette Bening, heartbreakingly empathetic as a woman out of time – too old for youthful bohemia and too young for her stuffy peers, and determined to raise her teenage son to be enlightened and brilliant. Rare is a fictional world so peacefully captivating. A24 The 40 best films of the decade 9. You Were Never Really Here Cinema is often at its most triumphant when it’s used as a tool for empathy, letting us climb into someone else’s brain and experience things that feel miles away from our own reality. That’s the revelatory power of Lynne Ramsay’s portrait of a PTSD-suffering vigilante, brought to life with incredible vulnerability by Joaquin Phoenix. Amazon Studios The 40 best films of the decade 8. Mad Max: Fury Road In a recent interview, Parasite director Bong Joon-ho revealed that he’d shed a tear while watching George Miller’s unexpected return to the Mad Max franchise. He called it “something we cannot describe with our words: all we can do is just cry”. He’s right. Fury Road is, essentially, a feature-length car chase – but it’s hard to put into words how epic and symphonic it truly is. CL Warner Bros The 40 best films of the decade 7. Paddington 2 A soothing balm for all of our socio-political ills, Paddington 2 is the film we needed more than any other this decade. There are numerous delights here, from the majesty of Paul King and Simon Farnaby’s script and its elaborate sleights of hand, to a moustache-twirling Hugh Grant at his most magnificent. But more than anything, Paddington 2 is about the healing power of community and family, a message conveyed with wholesome warmth and pluck by the achingly sweet bear of the title. Michael Bond would be proud. The 40 best films of the decade 6. American Honey It took a woman from Dartford to capture the sprawling, stirring power of the American road and all that it promises. Of all the decade’s films, Andrea Arnold’s American Honey feels the most hungry to exist independently on its own, ignoring the rules of storytelling and bursting at the seams with wildness and colour. Sasha Lane – who had never acted before she was spotted by Arnold on a beach during spring break – plays working-class teenager Star, who yearns for a greater purpose and hitches a ride with a truckful of kids as adrift as she is. AW Universal Pictures The 40 best films of the decade 5. Inside Llewyn Davis Inside Llewyn Davis is a kind of anti-Odyssey. In its story of a folk singer (Oscar Isaac) who hops from couch to couch, with no direction and few prospects, Llewyn becomes the weary Greek hero who not only struggles to find a way home, but realises he may not have a home to go to. It’s a deeply melancholic work. CBS Films The 40 best films of the decade 4. Phantom Thread Phantom Thread is a love story in a funhouse mirror – fizzy and feather-light, but with a barbed and kinky underbelly that could only have come from the mind of Paul Thomas Anderson. The bewitching duo of Daniel Day-Lewis and Vicky Krieps play a fashion designer and his muse, who unearth new means to sustain their marriage. Anderson lingers over objects of beauty throughout – the lines of a fabric, the mess of a breakfast table, the colourful residue left over after the ball drops on New Year’s Eve. Apparently Day-Lewis’ final film, but what a blissful way to go out. AW Universal Pictures The 40 best films of the decade 3. Get Out Get Out sunk its teeth into culture in 2017, and hasn’t stopped biting. Jordan Peele’s horror satire is a polished, spooky and supremely well-executed chiller, but works even better as a deconstruction of race. In its sights are peak white centrism, the burdens and expectations of being black in America, and the untruths of the post-racial utopia many were fooled into embracing in the Obama era. No other film has reflected society in the 21st century more succinctly. AW Universal Pictures The 40 best films of the decade 2. Carol A magical reprieve from much of the queer romance canon, Carol is neither tragic nor sexually neutered, and is rich with snowy, expensive opulence. Todd Haynes’s 2015 masterpiece plays like a fairytale, kick-started by a misplaced pair of gloves, with Cate Blanchett and Rooney Mara acting on feelings that were considered unacceptable at the time. Deeply romantic, sexy and dramatic, it takes everything Haynes perfected in his Douglas Sirk-inspired drama Far from Heaven (2002), and maximises it. The 40 best films of the decade 1. Moonlight Barry Jenkins is destined to be one of the most important cinematic voices of the era. Moonlight is ample proof of that: there are very few debuts that feel this transportive, that fill the screen with this much raw beauty and human vulnerability. The director knows the power of gesture, and so the film’s emotional weight rests on a few shared glances, or one hand placed gently on another. In the intersection between race, sexuality and class, it crafts tender poetry. CL David Bornfriend/Kobal/Rex

When you told friends that you’d be playing Megyn Kelly, how did they react?

It was definitely awkward. In a weird way, the judgement she gets from a lot of people, I felt on me a little bit. But up until four weeks into shooting, I was still grappling with who she was as a person, and it wasn’t until I really zeroed in on that year-and-a-half of the story that I could actually defend her.

The film walks a fine line: Megyn is sympathetic when it comes to her sexual harassment, but Bombshell still includes some of her more controversial moments, like when she famously insisted on air that Santa Claus couldn’t be black.

There are things she has said that I’ve definitely had issues with, but it doesn’t invalidate how I feel about her struggle. Avoiding all of that stuff to get an emotional arc out of her character, I just didn’t want to be a part of that. By the way, if this was a movie about me – and I hope nobody ever does one – it would be filled with flaws and mistakes, and I wouldn’t want somebody to take those things away. I really do believe that what she and those women went through was messed up, even though they work for a network that I highly have issues with.

I would imagine that as the mother of two black children, you didn’t relish re-enacting her “Santa is white” segment.

[Emphatically] Thank you! Yeah, that was hard for me.

To play Megyn, you enlisted the Oscar-winning makeup artist Kazu Hiro, who transformed Gary Oldman into Winston Churchill. What else went into getting under her skin?

If I didn’t have Kazu, this would never have happened, but I just recently watched [footage] for a behind-the-scenes thing, and it was actually so off-putting because I’m in the prosthetics, but I’m not in character. I wasn’t doing this thing she does when she walks into a room, which I truly believe comes from years and years of having to prove herself.

Charlize Theron, Nicole Kidman and Margot Robbie in ‘Bombshell’ (Lionsgate)

What does she do when she walks in a room?

She leads with her jaw, and she has this very static, still posture that nothing can penetrate. It’s like, “I will not give you a physical read on me.” Even when she shares emotional stories, she protects herself at all times, but I am a true believer that strong behaviour in characters comes from an emotional need.

For instance, with Aileen Wuornos, her eyes were so wide and her jaw was always so tight, and when I did that for the first week of shooting, I just looked like a crazy person until I realised that behaviour came from the fact that she was 5ft 2 and had been homeless from the time she was 13. You’d pump yourself up like that because you were trying to tell the other guy, “Don’t mess with me. I’m bigger than you think I am”.

So what did you determine that Megyn’s emotional need was in the story?

During that year-and-a-half, she faced an incredible moral dilemma: She really liked Roger, and she gives him credit for her career and where she ended up. She’s also a very driven woman who didn’t want to be defined by [accusations of sexual harassment] and that’s unfortunately a big thing for a lot of women, where you don’t want the world to look at you like you’re a victim. Even a year or two after that experience, I saw Megyn speak at women’s forums, and the way she talked about it was in this really protective manner. Her defences come up even higher, and she becomes more lawyerly and journalistic about it.

So as not to be portrayed as a victim?

Yeah. I think that’s just how she copes with her pain. Maybe she does it differently in private – I don’t know about that. But that was hard for us because when you make a movie, you want to have those moments where you can break a character down and just have her be raw, and there was nothing that gave me enough evidence that it was the right thing to do with her.

So how do you find another way to indicate those emotional undercurrents?

There’s this moment where the lawyer at her deposition asks her, “Any long-term consequences?” It was the closest to an emotional break that I could get because of the stupidity behind a question like that. I mean, where do you even begin? In one of the takes, when the actor said that line, I felt something break and I didn’t answer the question. I’m so grateful that [the director] ended up using that moment.

Charlize Theron as Aileen Wuornos in ‘Monster’ (Newmarket Films)

In a key scene, we watch Roger Ailes (John Lithgow) coerce a low-level Fox News employee (Margot Robbie) to hike up her dress. As a producer, how do you portray a moment like that without exploiting Robbie herself?

My concern was making sure she was comfortable in the underwear she was wearing. All three of us – Nicole, Margot and I – have been nude in movies where it’s not about the nudity. I’ve also been nude in scenes where I felt incredibly empowered, which is not what you would imagine.

What the scene in Bombshell was more about, and what made this brutal to watch on the day, was the fact that you had Roger Ailes dictating how this was going to go and she didn’t have a say. It’s the belittling factor: “I am going to get you to do something that I know you’re incredibly uncomfortable with.” I think it’s having to placate his power that makes it almost unbearable to watch, way more than if he physically raped her in that scene.

Watching this has been eye-opening to a lot of people. Men, especially, go, “I had no idea women had to do things like that”. It’s humbling that you can create that kind of moment, because a lot of times you know people are going to say, “This is a woman’s movie, and men will not tap into this at all.” When men can emotionally engage with what we experience and be just as disturbed by it, it’s a powerful thing.

The film made me think of the actors that Harvey Weinstein is alleged to have harassed, like Ashley Judd and Mira Sorvino, and how he would marginalise them or pit other women against each other to maintain a system where he could stay on top.

Yeah, and he did that to everybody. Pitting women against each other? He was really, really good at that. There was a lot of, like, “Well, I’m talking to Gwyneth for this movie...” One of his lines was that Renée [Zellweger] and I slept with him to get jobs. There was no limit to him. Even in the sexual favours, he would still pit us against each other.

Bombshell is a movie about women, but some viewers may be surprised that it was still written by a man (Charles Randolph) and directed by one, too (Jay Roach).

Well, the easiest response I can come up with is a woman didn’t decide to tell the story. If this was an article that I bought for my production company, I think my first instinct would be to go to a woman, but I didn’t pick the writer. The writer picked the story and did all the work on his own.

But this is such a great example of how we should not compartmentalise these stories to just one particular sex being able to tell it. I want to see more opportunity for female writers and filmmakers, but I also think that it’s a mistake to isolate men completely from that process. When you find the right man to tell that story, there’s real value in that.

Listen, we should always question this stuff, and I’m totally open to the conversation around it, but if I had to do it all over again, I would do it exactly the same way. The men in my life are incredibly compassionate and ask questions about things in a way that is inspiring to me. Why would I eliminate that interest?

Bombshell is released in UK cinemas on 24 January