I just like voicing films in general. I do a lot of documentary work and it's a short hop really to narrating a character, especially if you're on film and you're there in a visual way. It sounds obvious, but voicing an animation really focuses you on the way that you're communicating through your voice. It's a very specific ability that you need to be able to have in order to pitch it just right.

The idea of transformation - playing something I'm not - is the bit I enjoy most about acting.

Interestingly, this character [Doctor Nash] is probably closer to me than somebody like the evil Sir Godfrey in Robin Hood or Lord Blackwood who wants to take over the world in Sherlock Holmes. This is a character that's English, he's based in London, and so it's closer to me than a lot of stuff I've been doing recently.

I have an enormous amount of respect for Nicole Kidman. She's just done so many great movies and she's been out there at the forefront of carrying films and being a movie star. On set, it really pays dividends because when you're performing with her, she knows exactly how to play it. You don't have to compensate for her in any way.

Because I had children relatively late - in my 40s rather than in my 20s - it wasn't anything I ever knew that I would do. It kind of happened to me: I met the right woman and we had children. It was a revelation because it suddenly makes me realize "Oh, I get it. Now I know what to do with the rest of my life."

And I think in your 40s, you land a little bit, physically and mentally, you arrive at a place where you feel you've learned some stuff. Having children at that point meant I had something very useful to do for the next 20 years.

You need to try to find a way to humanize your villains. Genuine villains, in real life, still have mothers and daughters and sisters, and they fall in love. They don't walk around with a big sign saying, "Bad guy," on their head. They think they're good guys. If you can play that, I think it makes it more interesting.