In May 2004, Guillory starred in a new stage production of "The Shape of Things" at the New Ambassadors Theatre in London, with husband Cilenti. That year she also played her first big Hollywood role. She was cast as Jill Valentine, one of the lead characters in the video game adaptation sequel '. The film makers had searched widely for an actress to portray the video game character and found her in Guillory, who had to "please not only the movie-going audience but also the gamers." She was "a dead ringer for Jill Valentine". Guillory studied the original character's movements by watching playthroughs of the video game '. Before getting the script for the film, she had not been familiar with the video games or seen "Resident Evil" (2002).