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.
Jacqueline Hill
Grace Jacqueline Hill (17 December 1929 – 18 February 1993) was a British actress known for her role as Barbara Wright in the BBC science-fiction television series "Doctor Who". As the history teacher of Susan Foreman, the Doctor's granddaughter, Barbara was the first "Doctor Who" companion to appear on-screen in 1963, with Hill speaking the series' first words. She played the role for nearly two years, leaving the series in 1965 at the same time as fellow actor William Russell (who played the companion Ian Chesterton).