The two Doctors. Say, that's catchy...
During the Doctor Who panel inside Hall H at San Diego Comic-Con 2017, outgoing Twelfth Doctor Peter Capaldi was joined by Pearl Mackie (Bill Potts), Matt Lucas (Nardole), Missy (Michelle Gomez), Mark Gatiss, and outgoing showrunner Steven Moffat to engage Whovians and reveal the title and first trailer for the 2017 Christmas Special, Capaldi and Moffat's final episode.
Titled "Twice Upon a Time", the 2017 Christmas Special sees the Twelfth Doctor encounter his first incarnation (played by David Bradley), with co-star Mark Gatiss as a World War One soldier known only as The Captain. In addition, the trailer revealed that Pearl Mackie will return as companion Bill Potts.
The one-minute trailer begins with William Hartnell's speech from his final story "The Tenth Planet" blended seamlessly into David Bradley reprising the scene. "Love, pride, hate, fear..." remarks the First Doctor, "...Have you no emotions, sir?"
We see a fleeting glimpse of the First Doctor with his companion Polly Wright (played by a new actress in the role originated by Anneke Wills), whose right hand is glowing with regenerative energy. We quickly cut to the Twelfth Doctor, whose hands are also glowing with regenerative energy.
"Something has gone very wrong with time," remarks the Twelfth Doctor as we see him and the First Doctor simultaneously step out of their respective TARDISes. "We're trapped inside a single moment."
The Doctors encounter The Captain, who asks "So sorry...I don't suppose either of you is a doctor?"
The Doctors look at one another for a moment, then the Twelfth Doctor replies, "Are you trying to be funny?"
The Captain is taken inside the First Doctor's TARDIS, which impresses him. "These police boxes...They're ever so good, aren't they?"
As the Doctors face some exploding things, Twelve remarks "We do have one little advantage."
"What advantage?" asks One.
"There's two of us."
Lastly, we hear the voice of Bill Potts, who steps from the shadows and asks, "Is he here? Is the Doctor here?" This is followed by a glimpse of the Doctor and Bill hugging in a reunion.
Here's the trailer that was revealed during the SDCC panel, thanks to the official Doctor Who account on YouTube...
"Twice Upon a Time" will air December 25th on BBC America.