I've never been front and centre as an iconic American character [like in Doctor Strange]. Day to day, you know you're painting on a very big canvas.

I really cannot get over the generosity of our Tibetian teacher. He said, "Don't punish yourself. You're going to be a student at a university in the north of England. You need to have your experiences and have your fun, and not judge yourself. Don't live in guilt and regret."

[on BBC's Sherlock] It's a rare challenge, both for the audience and an actor, to take part in something with this level of intelligence and wit. You have to really enjoy it. It's a form of mental and physical gymnastics.

It's an interesting arc. You start with a character [Doctor Strange] who's likeable and charming but very arrogant and distant. He's funny but you can see there are massive holes in his life. It's a very painful transition and all that he becomes is tested so quickly and violently.

Landing the role of Stephen Hawking was the most positively surprising thing that has happened to me.

I'm always keen to use my body in my work, so I'm looking forward to the motion capture for Smaug. Both Gollum and King Kong were primates, whereas I'm playing a serpent, so it'll be interesting - I'll have to tie my legs together, possibly, or else they'll be kind of splayed out to the side as a reptile's should be.

We all want to escape our circumstances, don't we? Especially if you are an actor.