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.
Lalla Ward
After "Doctor Who", she appeared in the TV movie "Schoolgirl Chums" (1982), and "The Jeweller's Shop" and "The Rehearsal" on stage. Ward decided to end her acting career after marrying Richard Dawkins. However, she has since reprised the character of Romana in the 1993 charity special "Dimensions in Time," the 2003 webcast version of "Shada", and in several "Doctor Who" and "Gallifrey" audio plays produced by Big Finish Productions. She also played the 'Mistress' opposite John Leeson's 'K-9' in two audio plays from BBV. In addition, she has appeared at a number of "Doctor Who" conventions and related special events. In November 2013 she appeared in the one-off 50th anniversary comedy homage "The Five(ish) Doctors Reboot".