Doctor Who special to air on New Year's Day
The 11th series of the BBC sci-fi hit, and Jodie Whittaker's first as the Time Lord, ended earlier in December and the programme will not be back for a full run until 2020.
However, the show's festive special was moved back from its regular Christmas Day slot so Whittaker will investigate a new mystery with sidekicks Bradley Walsh, Mandip Gill and Tosin Cole on Tuesday.
A brief preview clip on the show's official Twitter account shows the Doctor talking about the discovery of the DNA "of the most dangerous creature in the universe".
And showrunner Chris Chibnall has previously said the episode will provide "big emotion for all the family".
"There's an epic scale to this adventure, we're going across time and space," he said.
"There's a lot of action, there's a lot of scares, some great new characters, it's another big cinematic slice of Doctor Who."
The Doctor Who special airs at 7pm on BBC One on New Year's Day.