"Twice Upon a Time" is an episode of the British science fiction television series Doctor Who, written by Steven Moffat, directed by Rachel Talalay, and was broadcast as the thirteenth Christmas special on 25 December 2017 on BBC One. It features the final regular appearance of Peter Capaldi as the Twelfth Doctor, the first official appearance of Jodie Whittaker as the Thirteenth Doctor, and guest-stars David Bradley as the First Doctor, having previously portrayed original First Doctor actor William Hartnell in the 2013 docudrama An Adventure in Space and Time. Pearl Mackie guest stars as the Twelfth Doctor's former companion Bill Potts, while his other companions make guest appearances - Jenna Coleman as Clara Oswald and Matt Lucas as Nardole.

This episode is a continuation of events after "The Doctor Falls", addressing the cliffhanger that it ended on, and takes place during the final story of the First Doctor; footage from the 1966 serial The Tenth Planet, is used in the special. "Twice Upon a Time" is Capaldi's fourth and final Christmas special as the Twelfth Doctor, and the last Doctor Who story to be written and produced by Moffat, who served as the show's executive producer and chief writer since taking over from Russell T Davies in 2010. After the special's broadcast, Moffat was succeeded as chief executive and showrunner by Chris Chibnall.

Since its broadcast, the special has received generally positive reviews from critics.

Wandering back to his TARDIS at the South Pole, the First Doctor, who refuses to regenerate and leave his companions behind, encounters the Twelfth Doctor outside his own TARDIS, in a similar state of mind after his previous ordeal. The pair are soon approached by a confused and injured First World War British captain, displaced from December 1914 while in a gun-point stalemate with a German soldier. All three are then abducted by a large spaceship, where inside they meet with Bill Potts; the Twelfth Doctor, however, doubts she is the real Bill. Upon encountering the ship's glass-like holographic pilot, they are offered freedom in exchange for allowing the ship to return the Captain to the moment of his death. Refusing to allow the Captain to die, the party escapes and takes the First Doctor's TARDIS to the planet Villengard.

Alone, the Twelfth Doctor meets with the rogue Dalek Rusty, who has taken refuge from the other Daleks hunting it. Given access to the Dalek Hivemind, the Doctor learns that the pilot and its ship, known as Testimony, were created on New Earth, designed to extract people from their timelines at the moment of their death, and archive their memories into glass avatars. "Bill" is one such avatar, created from her memories. Seeing no evil to fight, the Doctors agree to return the Captain to his timeline. Upon doing so, the Captain asks the Doctors to keep an eye on his family, introducing himself as Archibald Hamish Lethbridge-Stewart, a bloodline relative of the Doctor's close friend the Brigadier.^[1] As time resumes, the Doctors watch as soldiers on both sides begin singing "Silent Night". The Twelfth Doctor explains to the First that he deliberately shifted the Captain's timeline to the start of the Christmas truce, to ensure his life would be spared.

With the Captain saved, the First Doctor informs the Twelfth that he is prepared to regenerate and bids him good-bye before returning to his TARDIS. Now alone with Bill's avatar, the Doctor adamantly contends she is not the genuine Bill, only for her avatar to explain that memories are what define a person. To help him understand, the avatar restores the Doctor's memories of Clara Oswald before they are joined by Nardole's avatar. The Doctor refuses to give the avatars testimony of his life. They respect his wish to be alone and leave after he embraces them both. The Doctor then returns to the TARDIS and decides to regenerate, but not before relaying advice to his next incarnation.

While the Thirteenth Doctor examines her reflection, the TARDIS suffers multiple failures. Tumbling out of the ship, the Doctor observes the console room explode before the TARDIS dematerialises, as she plummets towards the Earth below.

"Twice Upon a Time" takes place towards the end of the First Doctor's final serial, The Tenth Planet (first broadcast in October 1966), some of which is shown at the start of the special. During the last episode's final moments, the Doctor leaves his companions Ben and Polly and returns to the TARDIS; they find him collapsed in the console room, where he undergoes his first regeneration. Derek Martinus, the episode's director, reportedly cut a line from the original script which suggested that the Doctor was refusing to give in to the regeneration process. Steven Moffat's 2017 story creates an extended narrative around that part of the story, in which the First Doctor delays his regeneration and encounters his future self — the Twelfth Doctor — in the snowy wasteland.^[2][3]

When Testimony shows the First Doctor images of his future incarnations, clips from both the classic series and the revival are used, including the Third Doctor from Invasion of the Dinosaurs; the Fifth Doctor from Arc of Infinity; the Seventh Doctor from The Happiness Patrol; the Eighth Doctor from "The Night of the Doctor"; the Ninth Doctor from "The Parting of the Ways"; and the Tenth Doctor from "The Waters of Mars".^[4]

Testimony also lists several of the Doctor's future titles: "The Shadow of the Valeyard" (from The Trial of a Time Lord, said to be an avatar of the Doctor's darker side), "the Oncoming Storm" ("The Parting of the Ways"), "the Imp of the Pandorica" (a reference to the Eleventh Doctor story "The Pandorica Opens"), "the Beast of Trenzalore" ("The Time of the Doctor"), "the Butcher of Skull Moon" and "the Doctor of War" ("Hell Bent"). "The Destroyer of Skaro" refers to the destruction of the planet in "Remembrance of the Daleks", although Skaro was later restored and rebuilt; as explained in "Asylum of the Daleks" and shown in "The Magician's Apprentice".^[4]

The Weapons Factories of Villengard were originally mentioned in "The Doctor Dances" (Steven Moffat's first Doctor Who story), where the Ninth Doctor implied that he was responsible for their destruction.^[5][6]

Bill's complaint that the Doctor cannot "see" her even when he looks right at her is the same grievance the newly-regenerated Doctor made to Clara Oswald in "Deep Breath" – that when she looked at him, she still could not readily accept that he was still the same man that he was before.^[4]

The Doctor addresses his original incarnation as "Mary Berry", "Corporal Jones", and "Mr. Pastry".^[7] Mr. Pastry was a children's show character played by actor Richard Hearne,^[8] who was once considered for the role of the Fourth Doctor. Hearne, however, wanted to play the Doctor as a version of Mr. Pastry, so he was passed over in favour of Tom Baker.^[7]

The Doctor paraphrases philosopher Bertrand Russell when he advises his future self that "hate is always foolish and love is always wise".^[9]

Peter Capaldi reprised his role as the Twelfth Doctor. On 30 January 2017, he confirmed that the tenth series would be his last, and that he was set to leave after the 2017 Christmas special.^[10] The episode also sees the introduction of Jodie Whittaker as the Thirteenth Doctor, whose casting was announced on 16 July 2017 following the 2017 Wimbledon Championships men's finals.^[11][12]

David Bradley appears in the episode as the First Doctor, having previously portrayed William Hartnell in the docudrama An Adventure in Space and Time.^[13][14][15] This makes him the third actor to play the role in the television programme, after William Hartnell and Richard Hurndall (in 1983's The Five Doctors) since the premiere of Doctor Who in 1963.^[16] Bradley previously played Solomon in the 2012 episode "Dinosaurs on a Spaceship".

The first trailer for the episode was shown during the 2017 San Diego Comic-Con, revealing the return of Polly, a companion from the end of William Hartnell's tenure as the First Doctor, who is to be portrayed by Lily Travers,^[17] and Pearl Mackie as Bill Potts, as well as a character played by Mark Gatiss named The Captain, marking his fourth acting appearance in the series.^[18][19] It also confirmed the appearance of Toby Whithouse, writer of seven episodes between 2006 and 2017, in the episode.^[20]

It was later confirmed that Ben Jackson, a companion of the First and Second Doctors, who served alongside Polly, would also feature in the episode and that he would be played by the former Hollyoaks cast member Jared Garfield.^[21] Hartnell, Anneke Wills and Michael Craze appeared as the First Doctor, Polly and Ben respectively through archive footage,^[22] as also did Patrick Troughton as the freshly regenerated Second Doctor. Nikki Amuka-Bird voices the "Glass Woman"^[23], her second appearance in the Doctor Who universe following her appearance in the Torchwood episode, "Sleeper".

As with the last change of showrunners, Chibnall wrote the final moments of the episode, so as to allow him to write Whittaker's first lines on the show. This happened in the 2010 special The End of Time, when Moffat took over for Russell T. Davies in the final moments of the episode, writing Matt Smith's first words as the Eleventh Doctor.^[24]

The episode includes a cameo appearance of Jenna Coleman as Clara Oswald, as the Doctor's memories of Clara, lost during "Hell Bent", are restored. The scene was the last to be filmed for the episode and while Coleman was willing to come back to film, timing between the filming of this special and her work in Victoria was difficult to arrange. Moffat said "How many times have I killed that girl off and she was right there in my last shot! It's absolutely extraordinary. The unkillable Coleman!"^[25]

The episode was written by Steven Moffat and directed by Rachel Talalay,^[26] who wrote and directed the two-part finale of the tenth series, "World Enough and Time" / "The Doctor Falls", respectively.^[27][28] In January 2016, Moffat announced that he would step down as the programme's showrunner after the tenth series, to be replaced by Chris Chibnall beginning with the eleventh series in 2018, but a 2017 Christmas special was not mentioned in the plans at that time.^[29] The change in showrunners almost caused the annual episode to be cancelled, as Moffat planned to leave after the tenth series finale and Chibnall did not want to begin his run with a Christmas special. When he learned of Chibnall's plans, Moffat elected to stay long enough to produce one final episode, as he was concerned that the show would lose the coveted 25 December slot in the future if it missed a year. As a result, he had to rewrite his plans for the tenth series finale to allow Capaldi to appear in one more episode.^[30]

Near the end of the special, the two Doctors part company and return to their respective TARDISes to undergo regeneration. The First Doctor's regeneration is shown, using original footage from "The Tenth Planet". Although the last episode of the 1966 story is one of the missing episodes of Doctor Who, the regeneration sequence was preserved when it was used in a 1973 edition of the children’s magazine programme Blue Peter.^[2][31]

The final scene of "The Doctor Falls" involving David Bradley was filmed as part of the filming of "Twice Upon a Time" in June 2017.^[32] Production for "Twice Upon a Time" started on 12 June 2017, and concluded on 10 July 2017.^[33][34][35] However, the final scene of the episode, in which Whittaker makes her debut as the Doctor, was not filmed until 19 July.^[36] The episode had been reportedly titled "The Doctors", before it was announced at the 2017 San Diego Comic-Con that it would officially be titled "Twice Upon a Time".^[37][19]

The episode was watched by 5.70 million viewers overnight in the U.K making it the second lowest overnight viewership for a Christmas Special, but was the fifth most watched programme of the day across all channels.^[38]

"Twice Upon a Time" was released in cinemas in multiple countries, including Brazil on 25 December, Australia and Denmark on 26 December, and the United States and Canada on 27–28 December. The cinema release includes two bonus features: a behind-the-scenes view of the episode, and a special celebrating the tenure of Peter Capaldi as the Doctor and Steven Moffat as showrunner and lead writer.^[39][40]

Professional ratings

Review scores
Source	Rating
Rotten Tomatoes (Tomatometer)	88%[41]
Rotten Tomatoes (Average Score)	6.69[41]
The A.V. Club	A-[42]
Entertainment Weekly	A[43]
SFX Magazine
TV Fanatic
IndieWire	C+[44]
IGN	9.5[45]
New York Magazine	[46]
Radio Times	[47]
Daily Mirror	[48]
The Telegraph	[49]

The episode received generally positive reviews.^[50] The episode currently holds a score of 88% on Rotten Tomatoes, with an average score of 6.69. The site's consensus reads "Doctor Who: Twice Upon a Time pays gratifying homage to the outgoing doctor while marking a thoughtful, warm, and funny passing of the torch to a new era in the franchise."^[41]

The episode will be released on DVD and Blu-ray in Region 2 on 22 January 2018,^[51] in Region 4 on 7 February 2018 and Region 1 on 20 February 2018.^[52][17]

A novelisation of the story, written by Paul Cornell, will be released in paperback and digital formats on 2 April 2018 as part of the Target Collection.^[53]

Wikiquote has quotations related to Twelfth Doctor.

• "Twice Upon a Time" at the BBC Doctor Who homepage
• "Twice Upon a Time" on Tardis Wiki, the Doctor Who Wiki
• Template:Brief
• "Twice Upon a Time (Doctor Who)" at IMDb

v t e Doctor Who: Multi-Doctor stories
Television	Major instances The Three Doctors "The Five Doctors" The Two Doctors Dimensions in Time "Time Crash" "The Day of the Doctor" "Twice Upon a Time" "Fugitive of the Judoon" "The Power of the Doctor" "The Giggle" Minor instances "The Name of the Doctor" "Deep Breath" "Listen" "The Doctor Falls" "The Timeless Children" "Once, Upon Time"
Audio	The Sirens of Time Zagreus 100 The Four Doctors The Eleven Cold Fusion
Books	Timewyrm: Genesys Timewyrm: Revelation Who Killed Kennedy Cold Fusion The Eight Doctors Players Interference – Book One Interference – Book Two The Colony of Lies Wolfsbane
Comics	Emperor of the Daleks Assimilation2
Video games	Dalek Attack Destiny of the Doctors Legacy Lego Dimensions
See also	Regeneration The Brain of Morbius The Trial of a Time Lord Dimensions in Time The Curse of Fatal Death "Journey's End" "The Big Bang" "Time" "The Rebel Flesh / "The Almost People" "Last Night" "Journey to the Centre of the TARDIS" "The Vanquishers"
Regeneration stories