Belief is everything when you're performing something. If you don't have the belief behind it, then that actually puts a shunt on the character. It's like, "Does the character believe this for a minute?"

I've been acting for years and years, at prep school - school plays, that kind of thing. That was always very high on my agenda. I went to study English for two reasons. Principally because when I was in university, studying drama wasn't considered an option. You couldn't get a degree course for it. And so many plays and things that I was interested in landed themselves in a broader spectrum of literature.

My first show, in England, was called Soldier, Soldier.

I think the level of devotion some sci-fi fans display turns other people off.

What would I like? Some very silly comedy where I don't have to think about anything, but it could be a lot of fun. And if it's not that, then I'll want to be involved in something where it's like, you're really dredged up to the neck in emotion, where it's as exciting as the premise of Battlestar.

Rather than, as an actor, I want the audience to like me, I'm going to smile beautifully and I've got everybody's sympathy - what about showing the moments when somebody is unbelievably petty? Or really selfish? The faults, the little things, those are the things that interested me about playing the character.

You can't find that moment when you became somebody else, because everything is in flux. So as it were, the torturous period where you are changing, you are transforming - I think that can be very hard on somebody's system. You don't necessarily realize that is what's happening.