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.
Leslie French
He also made the occasional foray into film and television, appearing in two Luchino Visconti films, "The Leopard" (1963) and "Death in Venice" (1971), as well as many popular British television programmes. These include "Dixon of Dock Green", "Armchair Theatre", "Z-Cars", "The Avengers" (the episode "You Have Just Been Murdered"), "Jason King" and "The Singing Detective". His role as Mr. Woodhouse in a BBC serial of Jane Austen's "Emma" (1960) is considered one of his most memorable screen performances. French was also considered for the role of the First Doctor in the science fiction series "Doctor Who", a part that eventually went to William Hartnell. He finally appeared in the programme in its 1988 serial, "Silver Nemesis", playing the Mathematician.