"It's the most expensive makeup I've ever had," says Oscar-winner Mark Rylance of his performance-capture title character in The BFG, Steven Spielberg's movie adaptation of Roald Dahl's classic book.

Mark Rylance at the premiere for The BFG

Rylance worked to develop every aspect of the Big Friendly Giant. One of the most distinctive elements was his gait, which had to be clearly non-human. "I think the discussion was on the first day of filming," Rylance says. "Steven said, 'Have you got BFG's walk?' And I thought, 'Oh, Christ!' But I said, 'Well, let's just have a go.' I mean the book describes the walk, this stopping and gliding, but it was a little while later that I found the walk that I wanted to use. I'm a stepfather, and Chris, my stepchildren's father, is a great friend of mine. He's a runner and he has a wonderful walk that I thought was right for BFG."

The character also required a special voice, which is one of Rylance's specialties in all of his roles. For the BFG, he was inspired by a recording from 1982. "There was an old, anonymous play called Arden of Faversham written around Shakespeare's time. I went to Faversham to see what it was like," Rylance says. There, he listened to and even recorded the residents to create just the right voice.

Rylance previously worked with Spielberg on Bridge of Spies, and enjoys the director's style. "What's nice, working with someone like Steven, is he's very flexible, and he really appreciates you jumping in and having a go, getting things wrong and trying things again," Rylance says. "Earlier on in my career, in Shakespeare, I used to try and interpret parts. But I think interpreting a part is not so helpful when you're acting. I think it leads to getting stuck."

And with The BFG, he enjoyed the challenge of acting in a performance-capture environment. "I felt enormous freedom," he says. "I didn't feel the freedom to f*** up his movie, but I had a freedom to play. That's where I like to find things. I felt more like a collaborator than any other film I've done."

And after years on the stage, Rylance is enjoying the chance to perform for a global cinema audience. "It means the world to me that the stories I'm telling are making people laugh," he says, "or moving people or just distracting them from the troubles of the world for a day and giving them a bit of strength to carry on."

Watch the trailer for The BFG: