From a very young age, I wanted to get up on stage whenever I went to the theatre - the actors just seemed to be having so much fun. One of my worries about theatre, in fact, is that the actors are quite often having more fun than the audience.

As an actor, you're just taking temperature. I am anyway, all the time, and responding appropriately. I was again cast very last-minute for Rushmore and met Wes Anderson, this quite physically and socially awkward man who didn't really talk to me much, a precocious and intelligent young boy. And Bill Murray. And we were sort of left in this bizarre hotel together and taken to strange locations around Houston. That was quite an isolating experience.

If the role is right and it's another situation of having a benevolent genius at the head of it, someone who likes actors, and will protect the actors from the ravages of reality-TV drama. It's a brutal world, and you need to have a strong creative team who can stand up to the network.

Working with Roman Polanski is funny. It's like anything in life - someone warns you that something's going to be amazing or difficult or awful, and you say, "I can do that. I can cope with that." And then when you're in the middle of it, it may be joyful or tricky, but it's never difficult in the way you think it's going to be difficult.

There's this absurd situation on a movie set where your trailer's here and the set is here and the lunch tent is here, and you're not allowed to get yourself from these three places.

I wanted to play a TV detective because it's a rite of passage; I wanted to experience every area of acting. I haven't done comedy or as much Shakespeare as I had intended.

I think it's quite lucky that I lead this lifestyle, and in fact, my career's only gotten better as I've looked older, because it ages you, the uncertainty.