A Doctor Who Christmas special is usually full of surprises – and if our recent set visit is anything to go by, this year’s festive special, which stars Matt Lucas, Greg Davies and recurring Who star Alex Kingston, isn’t going to disappoint.

Here Peter Capaldi tells TV Times about the Christmas Day episode, new companion rumours and the Christmas he became a Dalek…

So, what is the festive special like?

“It’s light-hearted and it’s a bit of an adventure. It’s also told in a very futuristic way, with flying saucers and robots – so it touches on a lot of Christmas themes but remains very Doctor Who-ish. And it begins with the TARDIS materialising on a Dickensian-looking street. The Doctor is being sort to perform a task…”

We know the man seeking him is a character known as Nardole (Matt Lucas), the messenger of monstrous ruler Hydroflax (Greg Davies). How does the Doctor react when he discovers that Hydroflax’s wife is none other than his old flame River Song (Alex Kingston)?

“There’s a complication there this time which hasn’t been there before. She doesn’t really know it’s him, so this time she’s basically flirting with everybody else, but him – which does bug him, to some degree. He gets to see her in the way that she normally behaves, and is quite appalled by it! So there’s a lot of flirting with other creatures, but none of it pointed in his direction.”

We understand your favourite Doctor Who festive special of recent years was the 2010 episode with Michael Gambon as a futuristic Scrooge?

“I love it when they go a bit Dickensian and I really like Michael Gambon. I think they’ve run out of national treasures now – we’ve been through them all!”

What presents did you get as a boy?

“My parents, God bless them, bought me a Dalek costume. The box had a very convincing illustration of what it was supposed to be. But when you opened it up, it was basically a dome with a plastic skirt and two holes that you stuck your hands through.”

Is there any hint in the Christmas episode about the new companion following Jenna Coleman’s departure?

“Not that I’m aware of. That doesn’t mean I haven’t met the new companion. It just means I don’t yet know what the outcome of it all is.”