I think an actor is very like a sportsman. You have periods where you're in terrific form. Everything you touch seems to work, and come right. And other times, when you're working really hard, it's okay, but it isn't scintillating.

'The Elephant Man' was hugely enjoyable to do. I thought the one stage, when Chris Tucker did the first makeup and it took 12 hours, I thought they'd actually found a way for me not to enjoy filming.

I first decided that I wanted to act when I was 9. And I was at a very bizarre prep school at the time, to say high Anglo-Catholic would be a real English understatement.

By the time I came to do the final ones [Harry Potter's film], I was working on something that was massively successful. There was a huge difference in indulgence and all sorts of stuff. A very big difference in peoples' attitudes. They were very pleased with themselves. In human terms, it was quite interesting to see the difference.

A mathematician either has a feeling for equations and an understanding and delight in it, not only in the purity of it, but in its beauty as well. I don't think that's something that you learn at school. I think you can get better in mathematics on a school level, but when you're talking about being a mathematician, I think that's definitely a gift of genes or whatever, you know? Whatever your pool is.

I got used to [ Lars Von Trier] doing the narration for 'Dogville' and 'Manderley.' And I said to him I do these narrations for you but you never put me in a film! So he called my bluff and put me in 'Melancholia' and I was thrilled about that.

I'm besotted by [Kirsten Dunst] now. I think she's just wonderful. I can't think for a second that however much she'd worked in America, she would never have had the chance to play [a role in Lars Von Trier's 'Melancholia' ] like that. You have to get outside of the States to do something like that.