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) future?" to which he replies, "It does start to happen, yeah." The series has played with the idea of a romantic relationship between the Ninth Doctor and Rose Tyler, with many characters assuming they were a couple. Rose's boyfriend Mickey Smith clearly views the Doctor as a romantic rival for whom Rose has left him. Each shows flashes of jealousy when the other flirts with other characters. In "The Parting of the Ways" (2005), the Doctor's male companion Jack Harkness kisses both the Doctor and Rose in what he believes is a last goodbye. In the same episode, the Doctor