BBC America released a trailer for their upcoming “Doctor Who” Christmas special.

The special, which marks Peter Capaldi‘s final appearance as The Doctor, will air on BBC America on Christmas Day.

In this year’s episode, “Twice Upon a Time,” Capaldi’s 12th Doctor encounters his former self, the First Doctor for an Arctic adventure.

David Bradley, who is best known to recent audiences as Walder Frey on “Game of Thrones,” takes on the role of the first Doctor. That part was originated by William Hartnell in 1963, but he is unavailable since he passed away in 1975.

This episode also reunites The Doctor with his most recent companion, Bill (Pearl Mackie).

For those unfamiliar with “Doctor Who,” The Doctor is a time lord from the planet Gallifrey. His name has never been revealed, but he can travel through all of time and space via his TARDIS, which is currently in the form of a British police box. The Doctor usually travels with a present day companion, and goes on adventures that usually involve saving various planets from catastrophic events. Rather than dying, The Doctor has the ability to regenerate, a process whereby he takes on a new appearance and a new personality.

Capaldi is the twelfth actor to play The Doctor. The series made headlines several months ago when it was announced that the thirteenth Doctor will be played by Jodie Whittaker. It will be the first time The Doctor has appeared as a woman.

The first “Doctor Who” Christmas special aired in 1965. But it would be 40 years before it became a tradition. When the series was revived in 2005 with Christopher Eccleston, the Christmas special became an annual tradition. It is generally a standalone episode. Eleventh Doctor Matt Smith also left the series in the Christmas special. You can read more about the Christmas episodes here.

Leading up to Christmas, BBC also announced a special farewell to Capaldi, complete with interviews and a retrospective. They will also run a marathon of all episodes of the show, beginning with tenth Doctor, David Tennant.

The “Doctor Who” Christmas special, “Twice Upon a Time,” will air on Christmas Day at 9PM.

Are you a fan of “Doctor Who?” What do you hope to see in the Christmas special? Comment below and share your thoughts!