Doctor Who (series 4) Astrid Peth, who died during the events of the episode. The companions in the regular series had all been in the lead companion role previously: the primary role of Donna Noble, who was introduced in "The Runaway Bride", was played by Catherine Tate for all thirteen episodes. Her return was announced by the BBC on 3 July 2007. Freema Agyeman, who portrayed the Doctor's companion Martha Jones in series three, returned for "The Sontaran Stratagem", "The Poison Sky", "The Doctor's Daughter", "The Stolen Earth" and "Journey's End". Billie Piper, who played Rose Tyler from the first episode of the new
The Doctor (Doctor Who) and therefore cannot be spoken. The character played by Peter Cushing in the films "Dr. Who and the Daleks" and "" referred to himself as "Dr. Who". However, these films are not considered part of the same narrative continuity as the television programme, as they were based upon two television serials featuring William Hartnell and made considerable alterations to the characters of the Doctor and his companions. Quite apart from his name, why the Doctor uses the title "The Doctor" has never been fully explained on screen. The Doctor, at first, said that he was not a physician, often referring