Twins of Evil is a 1971 horror film by Hammer Film Productions starring Peter Cushing, with Damien Thomas and former Playboy Playmates Mary and Madeleine Collinson, both real life twins .
It is the third film of The Karnstein Trilogy, based on the vampire tale Carmilla by Sheridan Le Fanu. The film has the least resemblance to the novel and adds a witchfinding theme to the vampire story. It is sometimes seen as a prequel to The Vampire Lovers, the first film in the Karnstein Trilogy, as the set design and costumes give the film an 18th Century look and feel.
Much of the interest of the film revolves around the contrasting evil and good natures of two beautiful sisters, Frieda and Maria Gellhorn (played by twinPlaymates Mary and Madeleine Collinson). Unlike the previous two entries in the series, this film contains only a brief vampire lesbian element.