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
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