Doctor Who Trailer for Final 60th Anniversary Special Teases David Tennant's Regeneration

Doctor Who has released a trailer for its third and final 60th anniversary special, "The Giggle." The episode sees the Doctor (David Tennant) and Donna Noble (Catherine Tate) squaring off with one of the Doctor's oldest enemies, The Toymaker (Neil Patrick Harris). The trailer also teases that Tennant's Fourteenth Doctor will regenerate into Ncuti Gatwa's Fifteenth Doctor in the episode. Written by showrunner Russell T Davies, and directed by Chanya Button, the synopsis for "The Giggle" reads, "The giggle of a mysterious puppet is driving the human race insane. When the Doctor discovers the return of the terrifying Toymaker, he faces a fight he can never win."

"You need an extraordinary actor to match David at the height of his powers," Davies told Total Film of casting Neil Patrick Harris as the Toymaker. "Bear in mind that this is David's TARDIS, his Doctor, his name in the titles. It's not easy for guest stars to come into that. You need that size, you need that experience, you need that skill to match him, otherwise you're in danger that the Doctor will tapdance all around you. That's what Neil brings… a vast performance that is properly terrifying."

Who is the Toymaker in Doctor Who?

In September, Doctor Who confirmed what fans had theorized, that Harris is playing the Toymaker in Doctor Who. Harris will play the role appear in the last of the three Doctor Who 60th-anniversary specials, titled "The Giggle."

Michael Gough originated the Toymaker character in the classic Doctor Who Series 3 serial The Celestial Toymaker, where the villain faced the First Doctor, played by William Hartnell. The Toymaker is a mischievous villain who enjoys trapping others and forcing them into playing childish games with their freedom at stake. The Toymaker is also a sore loser who rigs the games in his favor.

The Celestial Toymaker is the Toymaker's only appearance in Doctor Who television. Unfortunately, the serial is one of those lost Doctor Who episodes that fell victim to the BBC's then-policy of purging old material. Only its fourth and final episode, "The Final Test," remains intact. However, the audio track survived and has been re-released in audiobook format.

While the Toymaker only had one previous and one upcoming appearance in Doctor Who television, he's popped up in several other mediums, including facing off against Sylvester McCoy's Seventh Doctor in the Doctor Who audio serial The Magic Mousetrap. He's appeared in several comic book stories (most recently Titan Comics' Doctor Who 2015 Holiday Special) and the Fifth Doctor novel Divided Loyalties by Gary Russell.

How to watch Doctor Who Special Two: "Wild Blue Yonder"

The Doctor Who 60th-anniversary specials are airing on three consecutive Saturdays. Each special debuts at 6:30 p.m. on the BBC in the United Kingdom, and simulcasts streaming on Disney+ in international markets.

Doctor Who's third and final 60th-anniversary special, "The Giggle," debuts Saturday, December 9th on the BBC and Disney+. The Doctor Who Christmas Special will follow on Christmas Day.