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 (series 2)
The second series of British science fiction programme "Doctor Who" began on 25 December 2005 with the Christmas special "The Christmas Invasion". Following the special, a regular series of thirteen episodes was broadcast, starting with "New Earth" on 15 April 2006. In addition, two short special episodes were produced; and an interactive episode, as well as 13 "TARDISODEs".