There are things that I would avoid, so I have the choice to say no, when I feel I'm repeating myself too much. But then there could be a reason to do that with a good director. So I think actors have to have a loose philosophy.

I would absolutely like to play more leading roles. There's no philosophy - well, the only philosophy, I suppose, is to try and do different things.

Every now and then, they ask me to come in and improvise with Stanley Tucci for an afternoon. They fly me off to America, I improvise for an afternoon - it's not the hardest, most taxing job.

I went to meet Joe Johnston, the director, and he's charming. I've been very lucky. Most of the directors I've worked with are charming. But Joe's a particularly charming man, and he showed me lots of designs and, rather memorably, welcomed me to the Marvel Universe.