Doctor Who will take on a superhero storyline for the show's Christmas special, with Peter Capaldi returning in the title role.
Here are five things to know about The Return of Doctor Mysterio.
1) The show will borrow from traditional superhero stories.
The Ghost comes with a secret identity, a mask and a cape and showrunner Steven Moffat has said: "It's about a superhero fan who gets super powers so he's takes inspiration from all of them but Superman is the main one."
Peter added: "There is a kind of lovely wit that you have in the early Christopher Reeve Superman movies.
"Even if you watch the old Batmans with Adam West there is a tremendous tongue in cheek humour which has slightly vanished from the world of superheroes and I think that happens in the Return of Doctor Mysterio."
2) There will be a Lois Lane-style character in the show.
Charity Wakefield takes on the role of investigative journalist Lucy Fletcher, who teams up with the Doctor to get to the bottom of a sinister mystery.
3) Matt Lucas returns to the show as Nardole and Peter says the Doctor will be pleased to see him.
"I think it's a prickly relationship but I think he enjoys that prickly relationship. Matt is fantastic, he's hilarious but it's a slightly more complex performance than we had last time and I think there is a real chemistry between him and the Doctor, which is good," he said.
4) The episode is set in New York City
Peter has revealed there are some terrifying stunts. He said: "Being on top of the Empire State Building was about as dangerous as it sounds but not quite, that will be explained later.
"It was more troubling than I expected it to be because we were with a young actor - and when there is a young person on the set everybody looks after the young person - and the older person is left slightly to their own devices. But the older person had to go much higher than the young person and noticed there was no crash mats under him so then had to draw attention to that."
5) The title comes from the show's huge popularity in Latin America.
Peter has said he was delighted when he visited Mexico and found that was how his character was referred to in dubbed episodes.
Doctor Who: The Return of Doctor Mysterio will air on Christmas Day on BBC One at 5.45pm.