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.
Peter Purves
At twenty-six years old, Purves first became known to television audiences in 1965 as Steven Taylor, one of the early time-travelling companions in the programme "Doctor Who", when the Doctor was played by William Hartnell. He has provided DVD commentaries for many of the surviving "Doctor Who" episodes he appeared in and documents the making of each of his "Doctor Who" stories in his autobiography, "Here's One I Wrote Earlier". He was also a good friend of the actor Jon Pertwee, who played the Third Doctor.