“Some people do get very excited when they meet you and I feel vaguely confused by that because I don’t think I’m very exciting – I get into a panic because I think I mustn’t disappoint them,” admits Peter, 58.

“Doctor Who is exciting, but I’m not. I don’t know what to do. I can’t be myself because that will disappoint them.

“Often people ask for hugs and I can feel them shaking. Sometimes people can’t speak. I just hope that I give them a good time by talking to them.”

It’s been a tough year for Doctor Who fans, deprived of any new adventures after the next full series was put back to 2017.

Thankfully, there’s a Christmas special – titled The Return Of Doctor Mysterio – to save the day, which is set in New York and sees the Doctor getting involved with a masked superhero called The Ghost (Orphan Black’s Justin Chatwin), who is accidentally given his superpowers thanks to the Time Lord.

The Ghost’s connection to investigative journalist Lucy Fletcher (Charity Wakefield from Wolf Hall) is reminiscent of a certain well-known superhero’s bond with a reporter…

“There’s this Clark Kent/Lois Lane relationship which is very enjoyable to watch because you’ve got this almost farcical element of him having to hide his superhero persona,” says Peter.

“It’s a wonderful Christmas episode – very light and funny. I didn’t feel frustrated not being a superhero myself in it. I was quite happy not to be inside a rubber Lycra costume!”

Viewers will also be happy to see Matt Lucas return as unpredictable alien sidekick Nardole.

“It’s great having Matt back, he’s very funny,” smiles Peter.

“I don’t know if Matt will mind me saying this but when I see him on screen, he sort of looks like an alien.

“In a lot of his comic work, he has a very distinctive look about him, but in Doctor Who he genuinely looks like a creature from another planet, with his pale, sweet face and clear eyes. Together we sort of look like a pair of strange alien creatures, which is nice.”

Peter has some more good news for us: he has now fully recovered from the injury he sustained while filming the last series.

“I needed a knee operation because I ripped it chasing Zygons,” he says.

“That was in the middle of filming, so we just had to carry on. Then when we finished, I had surgery. The doctors always say: ‘Oh, you’ll be running around in a few weeks.’

“But you’re never running around in a few weeks. It took four or five weeks before I was able to hobble around on a stick, which I loved because it was rather theatrical.

“My wife had to stop me from buying a stick with a gold demon’s head.”

Peter’s injury is part of the reason the new episodes were delayed – not that him being off our screens brought him a quieter life.

“The funny thing I found is that I seem to have been recognised more this year,” he laughs.

“I can’t figure out how that works. I don’t know whether it’s just been available more on DVD or it’s nudged into the public consciousness more. But the recognition doesn’t seem to diminish when you’re not on TV. It seems to be as potent as ever.”

Peter’s own relationship as a fan of the show goes all the way back to his childhood.

But he says he was grateful for a recent encounter which reminded him how it feels to meet one of your idols, whatever your age.

“I was in a restaurant and someone said: ‘That’s Ray Davies from The Kinks,’” he reveals.

“I wasn’t sure at first if it was him, but this guy really looked like him. All I wanted to do was say hello and tell him: ‘You’re one of the greatest artists this country has ever produced.’

“I was extremely nervous, so I said it very quickly and he took my hand and talked to me and it was just wonderful.

“But what if he’d said: ‘Get lost! I’m having dinner’? It was a good reminder that I need to be gracious. People want very little. Just smile to them. I thought this is what kids must go through when they meet Doctor Who.”

NEW! Doctor Who Christmas Day 5.45pm BBC1