Jamie Bell becoming his boyhood hero

When Jamie Bell first pirouetted across the screen, as the ballet dancing Billy Elliott, his poise, grace and unaffected youthful exuberance charmed critics and endeared him to audiences all across the world.

He hasn't done much dancing since - "it's not that I actively avoided doing any dance movies, it's just that most of them being made these days aren't any good" - but his screen career has largely remained a steady run of supporting turns in big flicks like Flags of Our Fathers, Defiance, King Kong, and most recently Jane Eyre.

But now as the lead character in The Adventures of Tintin: The Secret of the Unicorn he's returned to boyhood and in a film, like Billy Elliott, that has tapped his physical performance skills.

"For me, that's what acting is all about: it's about taking on a challenging role and stretching yourself. It's about craft rather than just looking good, or trying to win a popularity contest."

The film, directed by Steven Spielberg using Weta Digital's motion capture computer animation, also tapped Bell's own enthusiasm for Herge's iconic character.

"I loved Tintin as a kid and spent many hours living my life vicariously through him," grins Bell. "I really admired his heroic qualities, his intellect and the fact that he got to race around the world in all these amazing machines. To get to do all that myself, in this film, is great.

"I love the fact that Tintin isn't your usual superhero because it's his brain that's his power, not his body which, let's face it, is physically that of a 16-year-old's."

For Bell, playing Tintin meant donning a specially designed suit and helmet and having his every act tracked. His performance was then enhanced by the animation techniques that created Gollum in Lord of the Rings and the giant ape in King Kong - both played by Andy Serkis who appears in Tintin as Captain Haddock.

"At first it's a little odd wearing a suit and helmet, and having dots all over your face. But as soon as you get past that and realise motion capture is just another way of recording your performance, then it's fine.

"Really, it's just another tool for me to express myself, a different way to play a character. Once I realised that, it became very liberating, freeing and fun."

Even more fun, he says, was getting to work with Spielberg and producer Peter Jackson, who'd previously cast him in King Kong.

"It's great to be working with two legends like Steven and Peter. That's about as good as it gets," Bell says. "Peter is someone who's always championed me and I'm extremely grateful for that. He's got endless enthusiasm, because even though he was writing The Hobbit at the time he was also always there to offer advice on Tintin. He even motion-captured himself as Haddock, which I saw, and it was amazing. It shows how passionate he is about this project."

The film isn't completely faithful to the books and is based on three instalments - The Crab with the Golden Claws, The Secret of the Unicorn and Red Rackham's Treasure.

"We've tried to stay as true to the characters and respect the universe that Herge created, while taking something that's very 20th century and bringing it into the 21st century with the technology that's now available. It was difficult, but I think we've pulled it off."

The rollercoaster ride of a film has already proved enough of a box office success that it looks like Bell will again don the motion capture suit with the news that Jackson will direct the second Tintin movie.

"I'd love to do another one because there's so much of the Tintin universe and so many other great characters that we haven't been able to squash into this one film. Having the chance to explore some more of those things would be unbelievable."