I have an enormous amount of respect for Nicole Kidman. She's just done so many great movies and she's been out there at the forefront of carrying films and being a movie star. On set, it really pays dividends because when you're performing with her, she knows exactly how to play it. You don't have to compensate for her in any way.

When you're making a psychological thriller, what you need to do is have an audience on shifting sand so they're never quite sure where they are.

I've put my friends and family through the wringer over the years, I have to say, by doing unspeakable things to people, not the least of which was pulling out poor George Clooney's fingernails in Syriana.

The idea of transformation - playing something I'm not - is the bit I enjoy most about acting.

Rowan Joffe is very specific. I mean, he wrote it as well and he has a very orderly writer's mind and the same applies to his directing.

Because I had children relatively late - in my 40s rather than in my 20s - it wasn't anything I ever knew that I would do. It kind of happened to me: I met the right woman and we had children. It was a revelation because it suddenly makes me realize "Oh, I get it. Now I know what to do with the rest of my life."

In the film industry you never really know if all the various ingredients will come together - sometimes they do, and sometimes they don't. As an actor, you don't have much control over those things. It's a director's medium in that sense. All you can really do is minimise the risks of being involved in something that might not work and look for something that also suits you.