For some lucky actors, there are moments when their career suddenly shifts into a higher gear. The right part comes along, the world notices, and boom! their whole life is different. This happened to Richard Madden with Bodyguard, in August last year. He played the tight-mouthed, tight-muscled David Budd, personal minder to Keeley Hawes’ home secretary, Julia Montague, in Jed Mercurio’s six-part BBC One thriller, and the country went bananas.

Bodyguard was great TV – gripping, unpredictable, sexy, with a madly OTT finale – but nobody could have predicted the furore it would cause. It was a national event, achieving the BBC’s largest drama audience for a decade. Social media was aflame every Sunday, with much of the heat centred on Madden, his good looks and his stoic “Ma’ams”. There were threads devoted to his eyebrows, as well as other parts of his anatomy. By the final episode, he had been upgraded from “ex-Game Of Thrones guy” (he played Robb Stark for the first three series) to potential James Bond.

Yet all this hype and bluster happened while Madden was busy doing something else. That something was Rocketman, the Elton John biopic. Madden plays John Reid, Elton’s first manager and one-time lover, and the script required him to sing and dance, neither of which are part of his natural skill set. So while Bodyguard was on, he was getting up to jazz-hands standard, while wearing a pair of 70s Cuban heels. “I loved those heels, in the end,” he says when we meet. “A double-breasted suit and a big Cuban heel. I felt pretty sharp. They gave me a bit of a wiggle.”

With Keeley Hawes in Bodyguard. Photograph: BBC

Madden knew that Bodyguard was doing well only because his mum kept sending him pictures of newspapers and magazines. “Like, ‘You’re on the cover of this one, and this one, and this one,’” he says cheerfully (his natural accent is Bodyguard Scottish, not GoT English). “It was nice, but it was also, ‘Please stop sending me this because it freaks me the eff out.’”

Six months on, his schedule is choreographed down to the minute. “That sudden loss of time,” he says. “Everything runs away with you. I’ve been really busy, yet there’s still more demand. You run with it, but it’s like, OK, we’re doing press for Bodyguard in America, and now we’re doing press for awards stuff, and then there’s the actual awards, and then more and more. And everything rolls into each other, so then you haven’t been in your house for two months.”

With his Golden Globe. Photograph: WireImage

That must be weird. “I don’t mind, really,” he says. “I don’t like my house that much. It doesn’t suit me. It’s a little three-bedroom family house that I bought because I thought that was what I should do. Basically, it’s my parents’ house. I should have got a really sexy one-bed loft in Clerkenwell.” He was trying to be sensible, but stardom was beckoning.

Madden has had a taste of this all-consuming busyness before: with Game Of Thrones, in his early 20s, and even before then, when he was cast, aged 12, in a BBC One series called Barmy Aunt Boomerang. So, he says, he knows enough for the shift in status not to go to his head – and he can cope with the attention. When he was in Game Of Thrones, he had a woman come up and just scream in his face. What did you do? “I waited for her to stop, and then asked her if she wanted a chat.” He smiles, a little ruefully: what can you do?

Anyway, Rocketman. I’ve only been allowed to see a taster, but it looks splashy and fun, with full-on musical numbers; at one point Elton and the audience levitate in the middle of Crocodile Rock. Taron Egerton plays Elton, and Jamie Bell is Bernie Taupin, Elton’s friend and lyricist. Madden hasn’t seen the film either, which makes things tricky, but we press on.

Rocketman has had some criticism around whether straight actors should play gay parts, so I ask Madden about this. “It’s a really terrible route to go down if we start restricting people’s casting based on their personal lives,” he says. “We have to focus more on diversity and having everyone represented, but I’m also a firm believer in the best actor for the part.” Madden has had high-profile actor girlfriends in the past – Jenna Coleman, Suki Waterhouse, Ellie Bamber – so I assume he’s straight, but some weeks after our interview, he’s linked with US actor Brandon Flynn, which would certainly flummox the critics. He steadfastly refuses to talk about his private life, speculation or not.

With Taron Egerton in Rocketman. Photograph: David Appleby

Madden has met Elton – “A very interesting and interested man, just lovely”; he was at his house the other day. He loved working with Egerton and director Dexter Fletcher (who also directed the final leg of Queen biopic Bohemian Rhapsody after Bryan Singer was fired) because they were both “so prepared. And that’s how I like to be, as prepared as possible, so we get on set and we can just play. Even with dancing, the point is to prep to oblivion so that I don’t think about it and can get on with telling the story.” Madden clearly had fun on Rocketman and wants it to do well. But after a while we return to Bodyguard.

He loved making the series, he says, but it was tough. It battered him, physically and mentally, because he was in so many scenes (standing saying nothing, tensely defusing bombs, rolling around in bed with Hawes and in a car pretending to be shot at, which was technically tricky). He’s self-deprecating about his work in the show – “Lots of eye acting. Days of it. Or just four pages of ‘Ma’am’s” – but when I press him, he says he’s proud of an early scene in which Montague asks Budd about his personal life; his marriage is under strain and he is separated from his young family. He likes it because he could have played it so that the audience could see Budd’s turmoil, but he didn’t. He played it mean and straight. Not likable.

“Likable is the actor’s flaw,” he says. “It’s something I’ve tried to shake off over the years. Most actors want to be liked and we want to make our work beautiful, not clunky and stilted. But that isn’t always the best way.”

It didn’t work, though, did it? The not-likable bit. Having so many people fall in love with him must be strange, especially when he was excited to be playing an antihero.

‘Likable is the actor’s flaw. It’s something I’ve tried to shake off.’ Photograph: Paul Farrell

“I spent my 20s playing Romeo,” he says. “Twice, literally, and then versions of it. So I was glad to move into my 30s [he’s 32] and be in a place where I might be the villain. I’m used to playing a guy with a few bad characteristics. With that, you think, ‘What has made you this way?’ and you justify them. But what was interesting with Bodyguard was realising that… sometimes people are bad. Or they’re good, but they change. This character was fun because he’s manipulative and snide in his tactics, and a bastard. You’re being dark, and you’re not justifying it. I enjoyed playing that.”

Madden won a National Television award and a Golden Globe for his performance. When he received the latter, he went up on stage, received the award, went backstage, all thrilled, “And then they said, ‘Just walk up these stairs.’ I walk up and I’m in a room with about 200 journalists.” He answered questions for hours.

Madden is a modern actor: he knows what’s required of him, all the promo, the glad-handing, the turning up. He once called Cara Delevingne unprofessional for not taking such things seriously, (she was sarcastic on morning TV, while promoting Paper Towns), pointing out that he did six weeks of interviews after playing Prince Charming in Cinderella, and was asked “the same eight questions”. As far as he’s concerned, if you can’t do that with grace, you shouldn’t bother.

Working, working, working. Is that all he’s about? “Not at all!” he protests. He went to the after-Globes parties with friends (“I did get proper drunk”), including Gemma Chan, who was there for Crazy Rich Asians. “We were both like, ‘What the fuck?’ She sees her movies nominated, I won an award. One year ago, we were sitting in my house thinking we were never going to work again and now we’re at these mad award ceremonies. It’s a headfuck.”

With Jenna Coleman at Glastonbury in 2014. Photograph: PA

Madden has a big friendship group of actors and is often photographed at Glastonbury festival – “my favourite place” – having a laugh, in the thick of Game Of Thrones chums such as Kit Harington, Rose Leslie and Alfie Allen. Despite his grace and gratefulness around his success, a part of him would like to chill out and do what he really enjoys, which is to read the papers on a Sunday, listen to Frank Sinatra (Sinatra At The Sands is his favourite album), or escape to somewhere wild, forget about exercising, drive lovely cars, maybe even get drunk. But that’s not happening right now. “I don’t have career ambition,” he says firmly. “I have life ambition.” It’s just that his career is taking him to good places at the moment. He tells me he’s thinking of moving to LA.

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Madden’s acting savvy is not the result of a showbiz background. The middle child of three, with an older and a younger sister, he grew up in a small town in the west of Scotland. His father was a firefighter, his mother stayed home until Madden was 11, when she got a job as a teacher in his old primary school. His parents were “hippies”, he says, and their house was pretty open, with friends always piling in for big vegetarian meals. Madden spent a lot of time outside, in the woods behind their house. He has several injuries: he shows me where he shot his dad’s old air pistol and blew off part of his finger, then managed to wreck the same finger when he nailed a wooden plank to his skateboard, then crashed it.

Aged 12, with Toyah Willcox in Barmy Aunt Boomerang. Photograph: BBC

He got into acting aged 11, when he joined a class to help with his shyness. One of his first jobs was a TV adaptation of Iain Banks’s novel Complicity. In it, Madden is so young as to be almost unrecognisable, with eyebrows that nobody would obsess over. The difficult thing about that job was that his character was raped. He certainly wasn’t traumatised by the role, but it didn’t make life at school easy. Then he got the lead part in Barmy Aunt Boomerang (Toyah Willcox played the eponymous aunt), so he didn’t really go to school much between the ages of 11 and 13, and when he went back, he struggled. He wasn’t academic, plus he had a problem with teachers who didn’t take children seriously. His parents were egalitarian, and as an actor he’d become used to grownups listening and giving him respect. “I always had this great interaction with adults,” he says. “But at school it was different, and I wasn’t having a good time with having been on the telly. I’d lost a bit of the joy of it. Acting wasn’t good for my life then. It’s like the opposite thing to making friends. It’s the one thing to guarantee you won’t have any.”

Never the sportiest of kids, he’d put on weight through on-set catering and became a target for bullies. He tells a great tale about his one and only fight: “I was really fat and this boy used to always give me abuse,” he says. “And I said, ‘Right, I’ll fight you at lunchtime’ to get it done with. And it got to the end of PE, and it was time to fight, and he says, ‘I’ll just go and get my lunch and then we’ll fight.’ And then he walked away. And five minutes later, I was like, ‘No. Fuck him. I’m not letting him get his lunch. We’re going to fight.’ So I go charging after him with 50 kids behind me.

“I find him at Tasty Bites with his roll and sausage. There’s a big crowd around us, and I’m just about to swing my first ever punch, in my first ever fight, and I feel this hand on the back of my blazer. I get dragged backwards and slammed on to the bonnet of a Renault 105, this old piece-of-shit car. It’s our car. And it’s my mum who’s grabbed me. She got a flat tyre on that street, on that day, saw this crowd of people, went over and saw me. Unbelievable! She went mad: ‘What are you doing? Don’t you be fighting at school.’ And it saved me because no one ever fought me again. They were like, ‘Oh, your mum will come.’”

He tells this story in a way that really makes me laugh – like the script for a short film – but it’s also interesting. Not because he was bullied, but because he stood up to the bully. There was self-esteem somewhere under the shyness. Anyway, he managed to plod through school. When he was 16, he realised that he missed acting, so he went back. It was excruciating, as his confidence had taken a battering, but he persevered and applied for drama school when he was 18. “If I’d failed, I would have reapplied the next year,” he says. “I couldn’t do anything else.”

He got in and immediately lost weight – “I didn’t want to be the fattest boy in drama school” – mostly by cutting out carbs. He still does this if he has to get into shape for a role; that and going to the gym, which he does first thing, because he wants to get it over and done with as he finds it so boring.

“I don’t like the look of me in the mirror,” he tells me, and I believe him. He doesn’t have the body language of someone who does. Even though he’s never short of romantic interest, there’s something in Madden that doesn’t feel handsome. It comes out in his comments about himself – like when he says that his favourite era for men’s suits is the 50s: “I love a high waist, always good for a fat lad.”

With Michelle Fairley in Game Of Thrones. Photograph: HBO

He is handsome, of course, though in a low-key way. But crikey, he really lights up in front of a camera. I see this the next day, on the photoshoot. The stylist and photographer are using a famous 1974 Terry O’Neill shot of a louche David Bowie as a reference point, and I’m not sure Madden will go for it. The suit is pink, with enormous shoulders and tent-like, pleated trousers. But to my surprise he loves it and immediately throws himself into character, chucking moves and shapes in front of the shutter. Suddenly, I get a glimpse of how brilliant Madden is at what he does. He’s utterly committed.

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A couple of weeks later, we speak on the phone. The career shift is continuing and he has moved to Hollywood: “The beach is nice to visit but I’m a Celt. Factor 50 every day.” Plus, excitingly for him, as he has to drive everywhere, he’s got himself a Jaguar S-Type. “It’s very sexy, very loud, with a bit of growl… You can’t write that, I sound like a proper twat. But I love cars, I love driving.”

With Lily James in Romeo And Juliet in 2016. Photograph: Johan Persson

He sounds very happy, despite everyone being cross on his behalf because he wasn’t nominated for best actor at the Baftas. “It’s not keeping me up at night,” he says. “I’m really thrilled for Keeley because she’s nominated, and that the show is, too. I’ve been very spoilt already.” Plus he’s too busy to worry about it. He’s landed a part in Sam Mendes’s first world war drama 1917, about which he’s excited, even though it means that, just as he moves to LA, he’s going to have to come back to England to film.

The only tiny worry on the horizon, if he’s honest, is whether he’ll be able to go to Glastonbury next month. He’s desperate to organise his schedule so that he can. And yes, he camps – “In a tragic one-man tent that’s too hot when it’s hot and freezing when it’s cold, and I come out with icicles on my beard” – although this year he’s thinking he’ll pitch himself somewhere near his friends, who all glamp.

The last time he went, in 2017, he found himself in the Lovebullets tent – “Wild Elrow circus madness, dancing to Fatboy Slim, brilliant”. He wants to have the same experience this year. I don’t have the heart to tell him that his life really has changed, and now he’s far too famous for that.

• Rocketman is released on 24 May.

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