Dr. Jekyll and Sister Hyde is a 1971 British horror film directed by Roy Ward Baker based on the 1886 novella Strange Case of Dr Jekyll and Mr Hyde by Robert Louis Stevenson. The film was made by British studio Hammer Film Productions and was their third adaptation of the story after The Ugly Duckling and The Two Faces of Dr. Jekyll. The film is notable for showing Jekyll transform into a female Hyde; it also incorporates into the plot aspects of the historical Jack the Ripper and Burke and Hare cases. The title characters were played by the film's stars, Ralph Bates and Martine Beswick.