Of this year's Christmas special, the actor told What's On Stage: "I play a character called The Doctor - a man who believes himself to be a Time Lord. It was great to be on board, because I’m a huge fan of the programme and of David Tennant.
"As for any talk of me taking over as the next Doctor," he said in response to the 11th Doctor rumours. "Well, if or when they do choose someone, they would have to be totally different to David - which I am."
Don't forget that the first two minutes of The Next Doctor will be shown during next Friday's Children In Need telethon on BBC One 7pm.