What is Villengard in the Doctor Who Christmas special?

However, it seems Villengard may be more powerful than ever in the upcoming special, with the official synopsis teasing: "An old enemy of the Doctor’s is lurking in the wings and all of human history hangs in the balance. Can the Doctor save Christmas, everywhere, all at once?"

So, what is Villengard and what makes it so dangerous? Here's everything you need to know.

What is Villengard in Doctor Who?

Villengard is a planet located in the centre of the universe that mass produces weapons in its fearsome weapons factories.

First introduced in the Christopher Eccleston story The Doctor Dances, the planet is known to produce weapons including sonic blasters. While it was only casually mentioned in Moffat's earlier stories, he's since increased the prominence of Villengard.

In Moffat's recent episode Boom, Villengard is at the core of the story, determining who lives and dies with its powerful algorithm.

It provides weaponry to the Clerics and assures a high casualty rate through its algorithm-run ambulances (played by Susan Twist), profiting from the warfare all the while. The end of the episode sees the Villengard mainframe destroyed by John Francis Vater (Joe Anderson).

In The Doctor Dances, the Ninth Doctor (Eccleston) recognises Captain Jack Harkness's (John Barrowman) sonic blaster as Villengard-made.

He asks if the Doctor had ever been to Villengard (once), with Jack saying the planet was destroyed when the main reactor went critical. The Doctor says there's now a banana grove where the factories once were.

While it's a casual reference, the full story is explored in the comic story The Whole Thing's Bananas, which sees the Doctor working with Dorium Maldovar to turn Villengard's factories into banana groves.

In Twice Upon a Time, the Twelfth Doctor visits Rusty, "the good Dalek" from the story Into the Dalek, in the ruins of Villengard. Rusty had set up a base for itself there, destroying all of the Daleks who came its way, leading to the ruins of Villengard being overrun by Dalek mutants.

What does Villengard want in the Doctor Who Christmas special?

In the Doctor Who Christmas special, Joy to the World, Villengard seemingly wants to grow its own star from a star seed, securing itself an unlimited energy source.

In a teaser clip for the episode, the Doctor finds a briefcase and uses his sonic screwdriver to project a hologram of Villengard's distinctive logo.

The Villengard hologram speaks through the Silurian hotel manager (played by Jonathan Aris), referencing the "collateral sacrifice" made by all beings in their attempt to grow a star.

While Villengard's plan initially seems out of the question, as they'd need around 65 million years to grow a star, the teaser trailer suddenly cuts to a Tyrannosaurus rex heading straight for the Doctor and Joy - making it clear that we've travelled back to the day of dinosaurs, and that they have pretty much exactly 65 million years to make their plan work... unless the Doctor can stop them, of course.

Doctor Who: Joy to the World will air on Wednesday 25th December on BBC One and BBC iPlayer at 5:10pm. Previous seasons are available to stream on BBC iPlayer.

Check out more of our Sci-Fi coverage or visit our TV Guide and Streaming Guide to see what's on tonight. For more from the biggest stars in TV, listen to The Radio Times Podcast.