This year’s Doctor Who Christmas special – fantastically entitled The Return of Doctor Mysterio – features a superhero known as the Ghost, the return of Matt Lucas’s Nardole and a New York setting. But beyond that we don’t know a huge amount.

So here’s showrunner Steven Moffat to tell RadioTimes.com a bit more about the origins of the Ghost, when we might have seen this year’s villains before, how Nardole came to be travelling with the Doctor and just how Christmassy (or not) the episode might be…

Could you run through the story and themes of the Christmas special for us?

“We’re doing a superhero episode so we have this character called ‘the Ghost’. I’d like to say we’re not doing a send-up of superheroes; we take it relatively seriously in a Doctor Who Christmas way. And we haven’t suddenly announced that superheroes are real in Doctor Who’s world. They’re not. It’s about a little boy (Logan Hoffman), who is accidentally conferred superpowers and who happens to be a comics fan and so he decides he should be a superhero in his adult years.”

Who is the Ghost?

“[His real name is] Grant Gordon. As an adult he’s played by Justin Chatwin. He played the lead in the American version of Shameless. I think he and Charity Wakefield [as Lucy] are absolutely gorgeous together in this, really lovely. It’s quite often the case with Doctor Who that when you’re watching you’re quite keen to get back to the Doctor, to his plot and that performance, but they kind of – as effectively as you can – pull focus from him. You’re quite happy spending time in their company.”

They’re a romantic item then, these two?

“Well, sort of. You’ll see, it’s the Lois Lane/Clark Kent thing playing out there.”

Would you say this is more like Superman than any other superhero tale?

“Yes, it’s what would happen if a little Superman fan was accidentally given Superman powers. What would he grow up to be? So it’s his model of how you behave as Superman. Which of course is not practical and not a way to live.”

What period is it set in?

“Most of it’s set in modern day New York.”

But am I right in thinking you didn’t do any filming in New York?

“We didn’t. We went to Bulgaria – as you naturally do when you go to New York – studios with a magnificent backlot of New York, which is fantastic and it looks like “movie New York”. It looks like the Christopher Reeve version of Superman and we have to matte proper New York onto the skyline. I think we’ll deliver a terrific New York. We’re still working on the effects for that and the monsters.”

So there are monsters in this then?

“There are monsters… There’s a proper villainous plot.”

All-new monsters?

“Not quite new. Fairly new. They’ve been around before. Something we’ve seen before but quite recently. It’s more fun if you don’t know. But there’s a sinister plot afoot to conquer the Earth and the Doctor is involved in stopping the plan and then stumbles upon the superhero he accidentally created. Which complicates matters.”

And how does Matt Lucas fit into the story?

“Well, he’s travelling with the Doctor when we first encounter him and it’s slowly pieced together what has happened to him, and continues to be pieced together throughout the next series. But you get the picture of what’s happened. We don’t ignore but we don’t make a big fuss of what happened last Christmas when we last saw him. He was decapitated but still alive because he was still inside Hydroflax. He’s lovely. He’s very good, Matt, I have to say.

“And it’ll be a relief to you, it’s got virtually no Christmas in it at all apart from the very first scene which has one solitary Christmas tree and the Doctor goes, ‘Ho, ho, ho,’ and that’s it. We ignore Christmas for the rest of it.”

Are you a Superman fan?

“I love the old Christopher Reeve Superman films and what they did with his secret identity with dorky Clark Kent and almost equally dorky Superman and the sort of love triangle for two they had going on in that. I found it very charming, so we’re going for that version of the superhero story. And I was fascinated as a kid by the idea of a secret identity because, while I fulfilled the remit for being dorky and useless, I just didn’t have a superhero alter ego to compensate for that. And I really wished I had!”

The Doctor Who Christmas special, The Return of Doctor Mysterio, is at 5:45pm on BBC1 on Christmas Day