The Doctor (Doctor Who) footage. Tom Baker did reappear, but as "the Curator", an ambiguously different character who he was not credited for playing. A voice actor, John Guilor, recorded a line of audio impersonating the First Doctor, for which he was credited as "Voice Over Artist". In other multi-Doctor stories, the multiple actors are all credited as "The Doctor", the exception being "The Three Doctors" (1972–73), which credited William Hartnell, Patrick Troughton and Jon Pertwee as "Doctor Who" as the 1972 serial preceded the practice of crediting the character as "The Doctor". In "Human Nature" (2007), the plot involves the Tenth Doctor altering
The Doctor (Doctor Who) about each other..." The narrative of series nine culminated in a three-part story arc in which Clara dies and the Doctor spends the next 4.5 billion years executing a gambit to change history and save her life. Further romance for the Twelfth Doctor was implied in the 2015 Christmas special, "The Husbands of River Song", in which this incarnation meets his one-time wife, River Song, for the first (and, narratively, the last) time. The spin-off media both before and after the television movie have toyed with the idea in various ways. In the 1995 Virgin New Adventures novel "Human Nature"