Peter Capaldi has said that despite being one of the older actors to take on the lead role in Doctor Who, he's still too young for the part.

The Thick Of It star is due to take over the role on Christmas Day, when Matt Smith's Time Lord will regenerate into him.

But Peter, 55, said he didn't think the Doctor would get too much of a shock at changing from looking like Matt, 31.

Doctor Who writer and producer Steven Moffat said: "The Doctor's thousands of years old, they've never been able to find an actor old enough to play him."

Peter agreed: "I'm 1,995 years too young to play him, really. So I think he's going to be quite happy to look his age."

Peter said he would be watching his first episode for the first time on Christmas Day along with the rest of the show's fans.

Asked if he was looking forward to the fans' reactions to his take on the Doctor, he said: "I haven't seen it, so I'm looking forward to my reaction. My family are all coming over to watch Matt Smith turning into me which will be interesting."

Peter said he was a fan of all the Doctor's previous incarnations: "All of them, I love them all, they're brilliant. They are just one, they're all of those actors and they're all a delight, I think they're all fabulous. I'm lucky to have them in my DNA because I've watched it from the year dot, so they're great."