I used to be absolutely addicted to the gym and I do still love it.

The way sci-fi works, you can never die.

I know it's really square but I'm one of those people who piles on the factor 50 as soon as I'm outside.

I found a lot of comfort in the fact that 30-odd people have been companions before me. I think that when there are so many people contributing so many things to the show, all you can do is make it your own. You can't try to emulate anyone, because who would you pick? The companions are very much the everyman, and the audience watches the story through their eyes, so they could be the person next door. And everybody's different.

Nobody in my family is in the show business, and none of my friends were. I went to a very academic school that actually - when I got to the point of wanting to pursue acting, they just had no idea how to do that, because all of their contacts were very academic.

Whether people watch Doctor Who or not over here, everybody knows about it. It's a British icon, it's so part of the nation.

I was very much into science when I was young - I wanted to be a marine biologist, then I wanted to be a doctor, and then something else, I was always changing. Acting didn't come up until much later, probably about 16 or 17. I thought, "Oh, I quite like this."