Twice Upon a Time (Doctor Who) The Doctor paraphrases philosopher Bertrand Russell when he advises his future self that "hate is always foolish and love is always wise". 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. The episode also sees the introduction of Jodie Whittaker as the Thirteenth Doctor, whose casting was announced on 16 July 2017. David Bradley appears in the episode as the First Doctor, having previously portrayed William Hartnell in the docudrama "An Adventure in Space
William Hartnell "The Name of the Doctor". The following story and the 50th anniversary special of the show, "The Day of the Doctor", featured two new pieces of dialogue for Hartnell's Doctor, recorded by John Guilor, who had previously voiced the actor in a reconstruction of "Planet of Giants". Hartnell's Doctor also made a silent cameo appearance in the Series 9 episode "The Witch's Familiar" (2015) again played by a body double. David Bradley, who portrayed Hartnell in the biopic "An Adventure in Space and Time", played the First Doctor in the Series 10 episode "The Doctor Falls", and the 2017 Christmas