Christopher, who is known for taking on weighty roles in dramas as well as playing the Time Lord, and who is starring in a John Lennon biopic for BBC4, showed his lighter side.
The actor, who has appeared in the BBC's dark comedy The League Of Gentlemen, told the Radio Times he had not worked since last year as he selects his TV roles so carefully.
He said: "I'm more slapdash about the film choices I make, whereas I choose my TV projects very carefully.
"But it's a tough time and I haven't worked since December because I'm choosy.
"I would actually like to do comedy for the rest of my life and surprise everyone and myself.
"My entire personal life has been a comedy, so I have experience."