The prosthetics were interesting because the artist was so good that they could just put a Hitchcock mask on me, but you don't want to do that. You're an actor playing Hitchcock, so it's about how much of that you're going to do.

I'm very interested in people, so if a character happens to be real, there's that much more to look at.

I don't know if it's harder but when you're playing a real person you want to honor their memory - even if they're a criminal or someone that the public loathed. That can be challenging.

I'm very fortunate that I get asked to do very different kinds of roles and I realize how much I enjoy that. I enjoy the challenge of transformation. There are actors who play one character, or a certain kind of character, the whole of their lives. I really relish the opportunity to have the challenge to totally transform.

When you're training as an actor, a lot of the big work you're learning is to treat fictional characters like real people. You don't have the problem of discovering a backstory with real people, but there's always a mystery which is common to both fictional and factual characters. They are never quite the person you think they are.

I still don't feel I know Hitchcock at all. I find that the more one looks, the more elusive he becomes. But my admiration for Hitchcock the filmmaker remains undiminished. He is a giant of the cinema and the darkness in him informs his cinematic language. You can't separate one from the other.

But I think the children of actors share a certain pragmatic approach. One is denied some of that 'running away with the circus' element of being an actor.