In 2003, after a friend had received a script for "The Principles of Lust", Guillory claims she "read it and couldn't put it down, and begged to read for the part". She was impressed by director Penny Woolcock's unconventional style of shooting, without rehearsing the actors, using raw takes and improvisational performances. For the role of Juliette, Guillory performed nude in the film's sex scenes which were filmed during the first week of filming, making her somewhat nervous. She later went on to say that it was one of her favorite acting experiences. Afterwards, Guillory had a small role in the romantic comedy "Love Actually" before taking the starring role in the television miniseries "Helen of Troy". The series was mostly based on Homer's epic poem "Iliad" and focuses on the mythological life of Helen. "Helen of Troy" was nominated for best miniseries at the Satellite Awards.