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
Doctor Who (series 1) considered for the role. Piper was announced as portraying Rose Tyler on 24 May, a character which fulfilled the role of permanent companion during the series, and was welcomed by fans of the show. Actress Georgia Moffett, daughter of Fifth Doctor actor Peter Davison and who would later appear as the title role in the fourth series episode "The Doctor's Daughter", also auditioned for the role. The original conception of Tyler was slightly different. Paul Abbott was scheduled to write an episode for the series which would have revealed that Rose's entire life had been manipulated by the Doctor in