Frazer Hines
Hines' "Doctor Who" debut came in 1966, when he was cast to play the part of Jamie McCrimmon, the companion of the Second Doctor (played by Patrick Troughton). Originally intended as a one-off guest character, Jamie joined the regular cast and appeared in the series from 1966 to 1969. Hines reprised the role in a cameo in the 20th anniversary serial "The Five Doctors" (1983) and as a guest star in "The Two Doctors" (1985). Hines would appear in 117 episodes of "Doctor Who" in all—more than any other "companion" actor in the history of the series. The only actors appearing in more episodes are those who played the first four Doctors. Many of the episodes featuring Jamie no longer exist in the BBC's collection.
Adam Mitchell (Doctor Who)
Adam Mitchell is a fictional character in the British science fiction television series "Doctor Who", played by Bruno Langley. Adam is introduced in the first series of the programme's revival as the second television companion of the Ninth Doctor (Christopher Eccleston). However, unlike the Ninth Doctor's primary companion, Rose Tyler (Billie Piper), who provided an effective human contrast to the Doctor's centuries-old alien, Adam was created to provide an example of an inept time traveller.