The star of Crimson Peak and Marvel’s Avengers – as well as High-Rise and I Saw the Light – bounds with enthusiasm. But for all the amiable sincerity, he is as cautious as he is courteous

Tom Hiddleston – quite late, very apologetic – has sorted us a table in the garden of his local, a posh pub in north London. He meets me inside, swoops up my stuff and strides out through the back door. “I’ve just always loved this garden,” he says. “It’s open and it’s light. It’s sunny and it’s vast.”

We head outside. Bit of decking, a few tables, small and otherwise deserted seating area. The noise of the 168 bus roars through the shrubbery wall. The sun dips behind a bookies across the road.

This, it transpires, is a key Hiddleston trait: a dogged, almost comical, enthusiasm for seeing the best in everything. Over the next two hours, he will talk unabashedly about the power of storytelling in his craft. He’ll quote Shakespeare, JG Ballard, Dylan Thomas, Eminem and his own sister. He’ll attempt – with some prodding – to untangle Tom Hiddleston, the actor, from “Tom Hiddleston”, the heart-throb. He’s extremely smart. Very careful to use the right words, very aware of their potential to be misconstrued. He is earnest. He knows that this is not cool.

“There’s just something very uncool about emotion,” he says. “Is that right? Perhaps that’s not quite right ... Passion is frequently uncool. And I’ve never been dispassionate for as long as I can remember. I’m so easily mocked. But that’s the reason I’m sitting in front of you.”

Hiddleston stars in Crimson Peak, Guillermo del Toro’s romantic horror about an innocent beauty (Mia Wasikowska) who is wooed by Sir Thomas Sharpe (Hiddleston), a handsome baronet who secures his new bride in his crumbling family pile. The spooky house squats on a hill of red clay. Scarlet gunk squelches up through the floorboards and slicks down the walls. Crimson Peak has ghouls in the brickwork, skeletons in the closet and a gremlin or two in its execution. It’s big on shocks, even if the plot gets spirited away.

Jessica Chastain plays Sharpe’s fearsome sister, Lucille. She believes life is harsh, but her brother is more of a romantic. What does Hiddleston think: is life beautiful or brutal?

“You come into contact with both,” he says. “You just have to respond the best way you can. Sometimes the brutality is humbling, and sometimes the beauty is surprising. It’s impossible to go through life without experiencing its random cruelty. But then, every day, there are so many things that are delightful. I’m not closed to any of it.”

Facebook Twitter Pinterest The film team review Crimson Peak

As Sharpe, Hiddleston’s performance hints at a savagery just beneath the surface. Many of his roles – from reckless Freddie in Terence Davies’s The Deep Blue Sea to Dr Robert Laing in Ben Wheatley’s upcoming adaptation of JG Ballard’s High-Rise – play off this. In Joanna Hogg’s Unrelated and Archipelago, his characters – boyish, rash and, sporadically, thoughtlessly nasty – are the small sparks that ignite the tinder. Even Loki, the Marvel universe demigod that rocketed him to international stardom, has a gentlemanly veneer. Hiddleston and Kenneth Branagh, director of Thor, in which Loki made his debut, were keen to give the character the complexity of a Shakespeare villain. As such, Hiddleston’s god of mischief is working through a jumble of relatable ills: sibling rivalry, abandonment, estrangement. It’s just unfortunate that world domination is also in the mix.

You would expect Hiddleston to share some of their darkness, but as well as being clever, funny and energetic, he’s also careful. He is deeply sincere in his love – of which he has a lot – for his co-stars, his director, his family, Roger Federer, the Rolling Stones, the idea of having kids, The Tree of Life, The Great Beauty, the Guardian, “the other place” (the Telegraph), the beer we’re drinking and the garden we’re sitting in. But for one so effusive, he’s also extremely precise – as cautious as he is courteous. He says his education (Eton, then double first in classics from Cambridge, then Rada) taught him to take care when speaking out.

Facebook Twitter Pinterest Tom Hiddleston as Loki ... working through sibling rivalry, abandonment and dreams of world domination. Photograph: Marvel Studios

“I think people should be rigorous about what they believe in,” he says. “The way I was taught was it’s just untenable to have an opinion you can’t back up. I think it’s very easy to adhere quite loosely to generalised opinions these days. I would never be so bold as to make a big public statement without making sure I fully believed in it.”

I tell him that’s very sensible, but he risks saying nothing at all. We run down a hit list of potentially interesting topics: equal pay for women in film (“It should be signed, sealed, delivered”), the biggest injustice in Hollywood today (the lack of credit given to crew), Jeremy Corbyn (“I find his integrity impressive”). Nothing really kicks off. He’s too quick-minded to be pinned down. I ask him who he voted for at the general election.

“I won’t tell you that.”

“Why not?”

“I’m not in the business of being politically divisive. I don’t want to set a precedent. It’s a private matter.”

I ask him what he believes in.

“I believe in kindness,” he says. “I believe very profoundly in that. I believe in bravery and courage, in being true to your word ... Very unfashionable.”

There’s something in Hiddleston’s lack of guile that makes it hard not to like him. His acting often incorporates a cruelty that in real life is completely absent. I think this is why his legion of fans – the “Hiddlestoners” (definition: “A devotee of the cult of Hiddles – someone who worships the glory that is Tom Hiddleston” – Urban Dictionary) – are besotted. He puts his heart and soul into all of the job – promotion included. So you believe him as he has fun when dancing his way around the talk-show circuit, or doing impressions, or hamming it up atrociously while selling us sports cars. He is, according to those who he’s acted with, an extraordinarily hard worker. The result is a performance, even in situations at their most engineered, that is as genuine as it is game. There is no front to any of it.

Facebook Twitter Pinterest Hiddleston with Mia Wasikowska in Crimson Peak. Photograph: Kerry Hayes/Allstar/Universal Pictures

“I have tried with all of my power for there not to be any inauthenticity,” he says. “There is no version of me presented to you that’s been created or is artificial. The people I’ve always respected have an integrity that is unassailable.”

The Hiddlestoner phenomenon, he says, is “an odd experience”.

“But I won’t be the first person to have thought that. I’m only in control of my own integrity. I’m accountable for everything I’ve done and I understand that. Everything else is out of my control”.

Josie Rourke, artistic director at the Donmar Warehouse, directed Hiddleston as the lead in the company’s acclaimed production of Coriolanus. She remembers, after the final performance last February, Hiddleston sitting up late into the night writing personalised thank-you notes on copies of the script for the cast and crew.

“People are increasingly hungry for context around the work in a digital age and he respects that,” she says. “Once two people literally walked through me to get to him. But he has the humility to deal with that need for him.”

“There’s three points of the triangle,” she says. “Tom, his fans and the media. Often, that last one is ignored. It’s in the interests of the media to talk about his fanbase because of the hits.”

“The reason I’ve chosen the projects I’ve chosen is to prove to myself and other people that I’m more than that,” says Hiddleston. “Perhaps the reason I do what I do is to prove that I’m not who you think I am. And I think part of the pleasure I get from acting is in defying expectations: my own and everyone else’s.”

Facebook Twitter Pinterest As Hank Williams with Bradley Whitford as Fred Rose in I Saw the Light. Photograph: Sam Emerson/Sony

No Hiddleston performance is more likely to do that than his work in I Saw the Light, Marc Abraham’s biopic of Hank Williams, which will be released, in time for a run at the Oscars, in November. Hiddleston stars as the legendary country singer, a long-term alcoholic who wrote and recorded the standards Your Cheatin’ Heart and Hey, Good Lookin’, before his death from heart failure at the age of 29. The film is wobbly, but Hiddleston is fantastic in it. He captures Hank’s mix of southern gentility and boozy ruthlessness. Grammy-winning country singer-songwriter Rodney Crowell helped Hiddleston become Hank: teaching him the songs, stripping away his classical training and steeping him in the American south.

“Sometimes we referred to Hank as the Snake,” says Crowell on the phone from Nashville. “Like, OK, Tom. You’re a good boy, but I need the Snake.”

Tom Hiddleston as Hank Williams – does his singing measure up? Read more

“One morning, I go up to his room and knock. I open the door and it’s Hank Williams. These dark slits for eyes. Then, slowly, the Snake receded and it was Tom again. He gave me that chuckle he does and said: ‘I was in there.’ He’s a very wise young man. A good salt.”

Back at the pub, we’ve wandered on to Tom Hiddleston’s new year’s resolutions. The ones he hasn’t kept: “No smoking” (“I did a bit when I played Hank. A stupid idea”); “Buy some new clothes” (I’ve seen his jacket on this press tour a fair bit); “Be on time for everyone” (he apologises again for his lateness). The ones he has: “Bleed less” (“I mean that literally. I have a habit of getting hurt. I got a big gash on my head when I was doing Coriolanus”); “Be careful of social media. It’s undermining and confusing.” And this one: “You’ve made a habit of playing so much outside your comfort zone it’s become comfortable. Your comfort zone’s what you’re frightened of.” Read it as Hiddleston would: serious, without any snark. Constant reinvention, striving to break free of preconception and repetition? That’s an admirable goal.

• Crimson Peak is released on 16 October. I Saw the Light is released later this year and High-Rise will play at the London film festival.