The BBC has released the first official clip from this year's Doctor Who Christmas Special, titled "Twice Upon A Time."

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In the clip, which you can see below, the Twelfth Doctor (Peter Capaldi) comes face to face with the First Doctor (David Bradley) and a man named the Captain (Mark Gatiss), who becomes a part of their story after being pulled from the trenches of the First World War. The episode sees the First Doctor struggling to accept his future self, having felt that he'd surely be "younger" than his present form. It's a light scene in what is sure to be an emotional episode with Capaldi's Doctor set to regenerate during the Christmas special as the actor leaves behind the role.

The episode will be the last for both Capaldi, who will be succeeded by Jodi Whittaker's Thirteenth Doctor, as well as Doctor Who showrunner Steven Moffat who helped usher in the new era of Doctor Who on the BBC . Recent rumors have suggested former Doctor Matt Smith will also be brought back for the forthcoming Christmas special, although those rumors appear to be just that for the time being.

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Whittaker, will officially make her debut as the Doctor in next month’s Doctor Who Christmas special, during which Peter Capaldi will bid farewell to the role.

She’ll be joined in the upcoming 11th season by Bradley Walsh (Law & Order: UK) as Graham, Tosin Cole (Hollyoaks) as Ryan, and Mandip Gill (Hollyoaks) as Yasmin. At that time Chris Chibnall (Broadchurch) will succeed Steven Moffat as head writer and executive producer. The new season of Doctor Who is expected to debut in Fall 2018.