Hammer's reimagining of the Robert Louis Stevenson story with gender roles reversed proves to be wonderfully entertaining. Dr. Jekyll and Sister Hyde was directed by Roy Ward Baker, with a script from Brian Clemens. The cast includes Ralph Bates, Martine Beswick, Gerald Sim, Lewis Fiander, Susan Brodrick, and Dorothy Alison. David Whitaker composed the music, and Norman Warwick handled the cinematography. Dr. Henry Shekel (Bates) is pursuing an elixir he believes will unlock the secret to extended life. He thinks this answer lies in female hormones sourced from cadavers provided by Burke and Hare. However, when the doctor experiments on himself, he undergoes a transformation into a captivating but dangerous woman. With London gripped by fear due to Jack the Ripper’s crimes, speculation arises: could Jekyll and Sister Hyde be connected to these killings? Burke in name, Berk in nature! The title is truly unfortunate; I am certain many have steered clear of this film simply because it sounded like a weak British horror spoof. That's a real loss, as it’s a delightfully fun movie that brings something new to a story that has seen countless adaptations on screen. Clemens’ clever script not only presents the transformed “creature” as a sultry and alluring figure in Martine Beswick’s form, but also cleverly weaves Jack the Ripper and Burke and Hare into the plot. There's even a playful nod to Sweeney Todd included. Murder, gruesome murder! Baker directs with a certain flair, keeping the film moving purposefully, while he, along with Norman Warwick and the set designers, create a classic Gaslight Gothic aesthetic – the ideal setting for such wicked events and gender-bending transformations. The scenes depicting the change are handled skillfully; the duality of beings and mirrors serve as a narrative strength. The movie isn’t hesitant to inject humor alongside the shocking Technicolor murders. In fact, some jokes are so understated that it's easy to understand why many contemporary film viewers missed them entirely – the subtle winks at the audience were lost on those who weren’t in on the joke. With Bates and Beswick delivering strong performances as the leads, convincingly portraying siblings, the film is consistently enjoyable. It rises above its initial concept to tell a story that feels fresh and original. Of course, there are some shortcomings in the production, but overall this is a Hammer film deserving of its cult following because it continues to reward repeated viewings. 8/10

Source on TMDB