The three special episodes are set to air in November 2023.

What's the plot?

That's a very good question.

Speaking at the time David Tennant and Catherine Tate's return as the Doctor and Donna was announced, showrunner Russell T Davies teased: "Maybe this is a missing story. Or a parallel world. Or a dream, or a trick, or a flashback. The only thing I can confirm is that it’s going to be spectacular, as two of our greatest stars reunite for the battle of a lifetime.”

We also know Heartstopper's Yasmin Finney has joined the cast as Rose, who will somehow be involved. And there's also a mysterious new character played by Neil Patrick Harris.

• Read more below: They're back... David Tennant and Catherine Tate return to Doctor Who