Second Doctor
The Second Doctor is an incarnation of the Doctor, the protagonist of the BBC science fiction television series "Doctor Who". He was portrayed by character actor Patrick Troughton.
Seventh Doctor
The Seventh Doctor and Ace appeared twice on television between the time "Doctor Who" was cancelled and the 1996 television movie. The first was in 1990, in a special episode of the BBC2 educational programme "Search Out Science". In this episode, the Doctor acted as a quiz show host, asking questions about astronomy; Ace, K-9 and "Cedric, from the planet Glurk" were the contestants. The Seventh Doctor then appeared in the 1993 charity special "Dimensions in Time". A picture of the Seventh Doctor appears briefly in the Tenth Doctor story "Human Nature" (2007), in John Smith's "A Journal of Impossible Things", and visions of him appear briefly in "The Next Doctor" (2008), "The Eleventh Hour" (2010), "Nightmare in Silver" and "The Name of the Doctor" (both 2013). He also appears in the 50th anniversary special "The Day of the Doctor" (2013) helping his past and future incarnations save Gallifrey from the Time War.