From Citizens to sequins for Prince Charming

Playing Prince Charming to Lily James' Cinderella posed its difficulties - not least the costume fittings. "You've got knee-high black boots and skintight white trousers on and you think, 'How am I going to pull this off? I have no idea! I'm literally wearing sequins!'" the bearded, blue-eyed Madden laughs. "I was terrified about it. Lots of standing against the wall because your bum's not covered and you feel very self-conscious, because you've got leggings on. You had to work at your confidence."

Madden's concern at compromising his masculinity is slightly comical, though perhaps understandable given he rose to fame as battle-hardened Robb Stark in HBO fantasy Game of Thrones. "When I first started talking about Cinderella, I said, 'Really, am I going to do this?' My agent sent me the script, and he's just had a baby and I thought he'd lost it and gone soppy." But then the 28 year-old read the script and realised this version was more to it than Hollywood schmaltz.

"There are three big deaths in the first forty minutes of the film," notes Madden. "We're not shying away from dealing with issues for kids. That's what Disney does so well. So there's a responsibility that came with taking on this role." Madden admits there was "no-one better" to guide him than Branagh. "[He] is the ultimate gentleman. A lot of my Prince is inspired by watching Ken." With the likes of Cate Blanchett and Helena Bonham Carter also starring, he calls it a daily "masterclass" - both in acting and how to behave on set.

When we meet, in Berlin, where Cinderella just received its world premiere, it's the day after Valentine's Day. So is Madden as romantic as his character? "Someone received flowers yesterday," he smiles, referring to his partner, Doctor Who star Jenna Coleman. He'll also be playing the ultimate lover next year, when he reunites with Lily James for a stage production of Romeo and Juliet at London's Garrick Theatre, with Branagh directing. Understandably, he's thrilled at working with Branagh for a second time. "There's no better compliment than him wanting to work with me again."

Madden's lived in London for the past decade, but he grew up in Renfrewshire "in a little village, which was a mile square, by a big forest", which sounds like a fairytale setting in itself. Raised with an older sister (now a bank manager) and a younger sister (a regional manager for an optical company), his mother is a classroom assistant and his father worked in the fire service. Acting came along simply because he was shy; he joined Paisley Arts Centre to "try and get a bit of confidence" before he transferred to secondary school.

It did more than just boost his self-assurance. By the age of 14, he was cast in the film adaptation of Iain Banks' Complicity. Later, he was accepted at the Royal Scottish Academy of Music and Drama, but a year into his studies, he won a role Franz Xaver Kroetz's play Tom Fool at Glasgow's Citizens' Theatre, which transferred to London. Once there, he was spotted by a team from the Globe theatre, where he swiftly won his first opportunity to play Shakespeare's Romeo in 2007. But it wasn't until Thrones that the game changed.

"I wouldn't be talking to you now if it wasn't for Game of Thrones," he admits. "I wouldn't be in this film [Cinderella]. It was such a great five years of my life, from pilot until finishing it." And what a way to finish; Madden was part of the infamous 'Red wedding' massacre that traumatized millions of unwitting viewers. "I had to keep it such a big secret, but of course, it is in the books that have been around for years!" he says. "That's why there are all these videos on the Internet of people shaking with laughter while others are screaming at the television!"

Since completing Cinderella, Madden has gone on film a new TV version of D.H. Lawrence's classic Lady Chatterley's Lover, co-starring Holliday Grainger in the title role. Cast as gamekeeper Mellors, he promises that it's not a version that's seeking controversy. "We're passed being shocked by anything. We've all got Google...we've seen all the boobs and bums that we need to see." He's also just wrapped Paris-set movie thriller Bastille Day, playing "a street-rat pickpocket" opposite Idris Elba. "There's a French Connection feel to it," he promises.

But what about locally? Would he be interested in returning to Scotland to shoot a movie? "I'd love to, but there's not a lot that gets made up there. I love being up there, apart from the weather, as much as I can." What he really wants to do is sci-fi, he confesses. "I'd love to have a nice laser gun on a space ship!" What about one of the upcoming Star Wars movies? They are being produced by Disney after all. "Yeah," he grins. "I'm in the family."

Cinderella opens on March 20th.