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.
Doctor Who: The First Doctor Adventures
The First Doctor Adventures is a Big Finish Productions audio play series based on the British television programme "Doctor Who". It sees the return of David Bradley as the First Doctor, a role originated by William Hartnell from 1963 to 1966, as well as by Bradley on television in the episodes "The Doctor Falls" and "Twice Upon a Time". David Bradley also portrayed William Hartnell in the BBC bio-drama, "An Adventure in Space and Time".