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
Harry Sullivan (Doctor Who) but he is apparently on some secret assignment and neither has seen him for a long time. Will is eventually revealed to be a sleeper agent of a religious cult targeting Sarah Jane, and dies during the course of the series. Harry appears in the Titan "Doctor Who" Ninth Doctor comic storyline "Official Secrets", set in the 1970s, where he briefly takes command of UNIT during the Brigadier's absence while investigating the mysterious appearance of large monsters, meeting the Ninth Doctor, Rose Tyler and Captain Jack Harkness during the crisis. A vision of Harry is seen along with every other