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.

It's great to have the chance to play a character before he goes to the dark side, or the yellow side if you will. Normally, you don't get that opportunity. The narrative of a movie usually demands that you are that guy from the start.

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 Secret Service I'm really excited about because Matthew Vaughn directed it. I've done a couple of movies with him - Stardust, which is one of my favorite films, and Kick-Ass, which is just a crazy, wonderful movie.

Rowan Joffe was on top of everything. He knew exactly how he wanted everything to be, right down to the fact when I made those telephone calls, I didn't do it afterwards in a studio. I think that's how he operates. He likes it to be as real and as clear as possible.

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

I had this extraordinarily bizarre moment when, two Fridays ago, my missus gave birth to our second child at 11am and by the same time the following day I was sitting around a table with Ridley Scott, Russell Crowe and Leonardo DiCaprio in Rabat in Morocco, rehearsing a scene we were going to shoot the next day.