Shelley Marie Hack (born July 6, 1947) is an American model, actress, producer, and political and media advisor. Hack is best remembered for her role as Tiffany Welles in the fourth season of the ABC television drama Charlie's Angels (1979–1980), replacing the departing Kate Jackson. Hack appeared in a total of 26 episodes of the series, before being replaced in season five by model-actress Tanya Roberts.