I, Monster is a 1971 British horror film directed by Stephen Weeks (his feature debut) for Amicus Productions. It is an adaptation of Robert Louis Stevenson's The Strange Case of Dr. Jekyll and Mr. Hyde, with the main characters' names changed to Dr. Charles Marlowe and Mr. Edward Blake. It stars Christopher Lee as the Doctor and his alter ego, and Peter Cushing as Frederick Utterson, a central character in Stevenson's original story. Mike Raven and Susan Jameson also star. It was photographed by Moray Grant, with music by Carl Davis. It was intended to be shown in 3-D, but the process was aborted mid-filming.