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.

My springboard is always the script. Even if the script is taken from a novel, I often haven't read the novel...

If it's a low-brow bawdy comedy, it's got to stand the chance of succeeding as such. If it's an intellectual piece, a drama, and so forth. And of course, once you've determined the level of the piece, do it the best you know how. And then don't make concessions. To audiences, or to pursestrings, or whatever.

In the States it's more and more difficult to get an independent film off the ground, and you certainly wont get the opportunity to play something like that in a studio movie.

When you're really working well with a director then you can be as outrageous as you like and so can he. And there's no worry about it.

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.