MANY actors shy away from watching themselves on screen, but not Peter Capaldi.

The Scotsman says he’ll definitely be tuning in to watch the Doctor Who Christmas special – although “it’ll be from behind the sofa!”

“I’ve always watched it, from before I was the Doctor,” he explains, during a break from filming scenes for the next series. “I’d watch it with my daughter, and it became part of our Christmas Day.

“Little did I know I was going to be playing that role – and now I have to watch it! I’d be depriving the family of one of the cornerstones of the day if I didn’t,” adds the actor, who has one daughter, Cecily, 23, with his wife, Elaine Collins.

This Christmas, the Doctor will be embarking on an epic New York adventure, when he and Nardole (a returning Matt Lucas) join up with investigative reporter Lucy (Charity Wakefield), and a mysterious figure known only as ‘The Ghost’ (Justin Chatwin), to try and save Manhattan from brain-swapping aliens.

“It reminds me rather of the early Superman movies with Christopher Reeve,” muses Capaldi, 58, who made his mark as The Thick Of It’s foul-mouthed spin doctor Malcolm Tucker.

“They had a great mix of irony and fun, thrills and chills, which on reflection is, in a way, how Doctor Who is. It has a very festive feel about it, without it being incredibly snowy and Bing Crosby-ish.”

Fans have already been treated to a movie-style trailer, which includes the Doctor being held at gunpoint and scurrying through prohibited corridors armed only with sushi.

“I just wave the food at my mouth,” reveals Capaldi on shooting those scenes.

“Many young actors do scenes with sausages and eat them on take one. By take 42, you are less enthusiastic... They might just be hungry young actors and the way the BBC pays, you’ve got to grab as many sausages as you can manage,” he teases.

It’ll be a year since we last checked in with the Doctor, and Capaldi - who’s busy filming series 10 with new companion Bill, played by Pearl Mackie, following Jenna Coleman’s departure as Clara - acknowledges: “The gap we had was more substantial than we normally have. I’m aware people are keen to see more, which is always nice to know.”

He believes the Christmas episode “is usually atypical of the body of the show; it plays to a wider audience”, but this special hints at a new, lighter tone.

Some bloggers have also applauded its camp quality. Is this something he embraces?

“I don’t know whether I embrace it, it just emerges,” he exclaims. “To me, there’s almost a B movie element about Doctor Who, which I’ve always loved. I look back at the old episodes and see how the actors remained truthful and committed in spite of cardboard walls and Copydex monsters.

“It’s less so nowadays, because the show looks as good as it does but is it camp? Yeah, I think it is, and very good it is because of that,” he continues.

“It’s lots of other things too. It’s scary, slightly edgy. We never take the mickey out of it. That would be absolute death to the playing of it but we always sail close to the wind.”

The show’s known for its passionate and loyal fan base, and Capaldi makes no secret that many of the enthusiasts know more about Doctor Who than he does.

“Absolutely, and good for them,” he says. “I always loved the show, was a big fan of it, but I was never, shall we say, of the trainspottery variety. I didn’t care about how accurate it is to the canon or whatever. It was irrelevant to me, even more so now!”

But he regards it as “a thing of great heart and spirit”.

“That’s what has to be preserved,” he says. “The thing about the show is it’s been going for over 50 years, but every episode is episode one, really. You can join it at any time. It’s not an exclusive club for people who are spending too long looking at old VHS tapes and DVDs. It’s a living, breathing show of today.”

Capaldi made his debut as the Doctor in 2013, and remembers feeling “very excited but very nervous”.

“I was happy with my life. I’d been very blessed already and there are things about doing the show that make life more complicated, certainly being so visible is a new and different way to be.”

But he adds: “It’s so delightful to be in this position. People aren’t really seeing me any more. They see Doctor Who, so it’s a fantastic place to be. It’s also finite, so I’m enjoying as it unfolds.”

Steven Moffat, lead writer and executive producer, has already announced series 10 is his last – he’ll be replaced by Chris Chibnall - and there are rumours Capaldi will follow suit.

Is it true?

“I’ve been asked to stay on and I haven’t made my mind up about that yet, mainly because I don’t want to have to make that decision,” he admits, laughing. “I’m trying to avoid it!”

The greatest influence, he says, will be “how good a time I was having”.

“Doctor Who does take a lot of time, but it’s a wonderful use of it,” he says. “It’s special. I’m lucky enough to be in touch with other Doctors, and we all agree how extraordinary it is to be in this position.

“To decide to leave is a tough decision for everybody. [It was] very tough for Steven, so I’m just putting it off for as long as possible.”

If he does decide to stay for series 11, which would start in 2018, it might mean he’d celebrate a landmark birthday as the Doctor.

“That would be a good way to spend your 60th birthday, don’t you think?” he says, and why not? As he remarks, “I’m very robust!”

The Doctor Who Christmas Special: The Return Of Doctor Mysterio airs on BBC One on Christmas Day.