Las dos caras del Dr. Jekyll

Christopher Lee's role as Paul Allen in the film was written especially for him and was one of his personal favorites.

Robert Louis Stevenson, the author of the novella that this film was based on, Strange Case of Dr. Jekyll and Mr. Hyde (1886), was never mentioned in its credits. Because Stevenson's novella was already in the public domain by that time and because Stevenson himself was long since dead (he had died in 1894), Hammer obviously felt no obligation to mention him in them at all.

Extensive cuts to the original UK theatrical version of the film were made by the BBFC in order to shorten the scenes where Maria dances with a snake, the scenes of brief nudity during Hyde's bedroom scene with Maria and the scene of Hyde strangling her. The 2010 U.S. Sony DVD version of it, however, which was released as one of the four films in the box set "Icons of Horror Collection: Hammer Films", features its restored and uncut UK theatrical version.

Featured in Movie Macabre: The Two Faces of Dr Jekyll (1986)