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.

I couldn't get any of the ingenue roles when younger because at 5 feet 9 inches with a deep voice I was always too... genue. My career has completely happened since I was 29.

The phrase you usually hear after a cut is "That was great. Perhaps we could have another go. Maybe try it this way." Even that much direction is prefaced with a lot of praise and encouragement. It's quite like how you deal with toddlers: positive reinforcement, and then a little suggestion that you might want to try something different. Roman Polanski will stop the take and shout, "No, no, no!" Which is somewhat alarming the first time it happens.

Ewan McGregor is a very genial and entertaining man, and Pierce Brosnan is possibly the nicest man in the world. Actually, it was quite a genial set The Ghost Writer, but the weather and the colors and the actual surroundings were oppressive. But it was a created atmosphere. What was so striking is that Roman Polanski had his crew from The Pianist, and we were shooting in Berlin, so there were German and Polish and French people, and I was just sort of enjoying being in this mix of people, all kind of rubbing along together. That felt good.

That was a bizarre and unlikely event, which has misled a generation of drama students from my old drama school that dreams really do come true. I was an unemployed actor. I had been an actor for about eight years, and had worked in theater, and done a tiny bit of TV, and somehow an audition video of mine ended up on Kevin Costner's television screen, and he rang me up and invited me to fly first-class to Hollywood and be in his movie The Postman.

Usually the casting process is lengthy and humiliating, but in this instance, The Ghost Writer, it was just too easy. I was sitting in a rental car on an L.A. street and my cell phone rang, and it was Roman Polanski on the line. I couldn't really believe my luck. He said, "See you in Berlin." I sat staring at a palm tree, thinking how surreal that was.

I am the worst judge of how a movie is going to do. I always have great and ambitious hopes, but none of them see the light of day.