PETER Capaldi believes playing Doctor Who is a bit like being Santa Claus.
The 57-year-old is the 12th actor to play the famous Time Lord in the long-running BBC sci-fi series, and he's not taking a single moment for granted.
"You become the fulcrum of the affection they (the fans) feel for the entire show, 50 years of it," Capaldi told APN during a recent visit to Sydney for the Doctor Who Festival.
"He's actually a piece of folklore. He's someone who exists in the imagination, so to be the living embodiment of that is a bit like being a department store Santa, you know, in a really good store with the proper gear, the proper elves."
The analogy is a timely one, with the annual Doctor Who Christmas Special premiering tonight.
It's a particularly meaningful time of year for Capaldi, who took over the role in his first full-time appearance in 2013's Christmas special, The Time of the Doctor.
"The Christmas special is fun. We've got snow and glitter ... it feels a little outside of the regular season of Doctor Who because it's a treat. It's like the Doctor is on holiday," he said.
"He's been through a lot (this season) and I think it's good for him to have a bit of a break."
The festive episode sees Alex Kingston reprise her role as Professor River Song, the Doctor's wife, whom she first played in 2008.
Also a time traveller, River Song (pictured) meets her husband's new incarnation (Capaldi) for the first time on Christmas Day.
"She thinks the Doctor only has 12 regenerations, so to have this other one, she thinks he's an impostor," Capaldi said.
"He's a bit offended by the flirting she does with other people. She doesn't do any flirting with him because she doesn't think he's the Doctor, and that really irritates him."
It's been a tough year for the Doctor, following the recent departure of his companion Clara (Jenna Coleman).
"He was deliberately trying to enjoy himself because he had a sense of something bad coming and something bad did come," he said.
"It puts him in a new place for next year; he's changed again and he was right to be suspicious."
Capaldi remained tight-lipped on what form the Doctor's next companion might take.
"The companion is crucial; he/she is how the audience sees the Doctor," he said.
"I've done 26 episodes now, which amazes me, and that amount of episodes gives you different character layers.
"Somebody has to come along to uncover new layers, so I'd like to see somebody who reflects the real world."
The complex humanoid character continues to challenge Capaldi, who is the oldest actor to play the Doctor since the show's return in 2006. He is more than 20 years older than his predecessor, Matt Smith, and plays a fiercer, more abrupt version of the protagonist.
"One of the reasons he's more difficult to play than you anticipate is that if he wants to, he can know everything," he said.
"There's a part of him that can see the future, and it means he knows the fate of the people he loves or the people around him.
"Chris Eccleston had a line in the first episode of new Who: 'I can see everything that has ever been and everything that ever will be and it drives me mad'.
"His perspective on life is deeper and longer than a human being's. But in order to have a life, you have to turn a lot of that stuff off or else it would just destroy you."
The Doctor Who Christmas Special airs tonight at 7.30pm on ABC1.