I have a kind of neutrality, physically, which has helped me. I have a face that can be made to look a lot better - or a lot worse.

But this is where you get all the market research and things get in danger of becoming formulaic, and where you depend on brands and getting recognised actors. It's the thing that precludes risk very often, otherwise everyone would be avant-garde all over the place.

I'd love to try my hand at something else.

When I visited coffee farms in Ethiopia, the farmers could not believe we spend a week's wages in their country on a cup of coffee in ours, because they see so little of the profits. Oxfam's fair trade campaign helps right this wrong.

It was mainly to do with Helen Hunt, to be honest. That's what drew my attention to it. I was interested in the fact that she was going to be directing. I'd never met her but she projects a degree of intelligence and it was convincing t me that she'd be able to handle this sort of material very well.

No matter how much technique you draw on or how much training you have, acting is a mystery.

Directors don't get to see other directors at work - they're the only one on the set. I've met directors who've asked me what another filmmaker is like. So, there's probably nobody better placed to make all the comparisons and to pick up stuff than an actor.