Doctor Who special The Giggle: Air time, cast and plot for final 60th anniversary episode

Just like that, David Tennant's return to Doctor Who is almost over, with the third 60th anniversary special The Giggle set to be his swansong on the BBC sci-fi series.

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While it will be sad to see Tennant and Catherine Tate bid farewell to the series once more, it will mean that it is time to welcome the next Doctor: Ncuti Gatwa.

Before that, though, here is everything you need to know about what is coming up on The Giggle.

When is Doctor Who special The Giggle on TV?

The Giggle will air on BBC One and on BBC iPlayer at 6.30pm on Saturday, 9 December, and the episode will have a runtime of just over an hour.

What is the plot for The Giggle?

The Giggle finds The Doctor facing an old enemy, no not The Master and not The Daleks of Cybermen. This time he is facing the Toymaker, a villain who hasn't appeared on the show since William Hartnell's era as the Time Lord.

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Following the shocking revelations in Wild Blue Yonder that the world has gone mad and people are beginning to turn on each other, it's up to The Doctor to face the person responsible.

Enter the Toymaker, who has the human race in the palm of his hands and is more terrifying that anyone can imagine, with The Doctor seemingly powerless to stop him — not that that will stop him and Donna from trying to save the world.

Who stars in The Giggle?

Neil Patrick Harris takes on the role of the Toymaker in The Giggle, the actor is known for his roles in series like How I Met Your Mother and the Harold & Kumar movies. He previously worked with Doctor Who showrunner Russell T Davies in It's A Sin, which is how he came to be cast in the BBC show.

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Harris will of course be joined by Tennant and Tate, who will be making their final appearances as The Doctor and Donna (in theory), and they will be joined by Charlie de Melo, who plays Charles Banerjee, and John Mackay as John Logie Baird.

Jemma Redgrave is set to return as UNIT's Head of Scientific Research Kate Stewart, as will Ruth Madeley as Shirley Ann Bingham.

Gatwa will also be making a brief appearance in the series as The Doctor, taking over the role from Tennant during the events of the special — likely towards the end of the episode.

Is there a trailer for The Giggle?

A brief teaser clip was shown for The Giggle following the release of Wild Blue Yonder, and the trailer showed a glimpse of Harris in character as well as The Doctor's regeneration and Gatwa's debut in the role.

Watch the trailer below:

Doctor Who's 60th anniversary special The Giggle premieres on BBC One and BBC iPlayer on Saturday, 9 December at 6.30pm.