Released on this day in 1971
Released on this day--17 Oct.--in 1971, Roy Ward Baker's DR. JEKYLL & SISTER HYDE, Hammer's excellent gender-swapping 3rd riff on the Robert Louis Stevenson novella. Ralph Bates, as Henry Jekyll, manages to turn himself into "Edwina Hyde," the breathtaking Martine Beswick, who seems to be having an absolute ball as his evil alter ego. The film was written by Brian Clemens, one of the real undersung stars of late Hammer horror, and beside Stevenson, his riot of a screenplay also manages to work in both the Jack the Ripper and Burke/Hare killings.
This wasn't the first time a Jekyll/Hyde movie incorporated a gender-swap--that would (as far as I know) A MODERN DR. JEKYLL, a little-remembered lost film from 1908--and it certainly wouldn't be the last (less than a year later, David F. Friedman had THE ADULT VERSION OF JEKYLL & HIDE on the screen, and more would follow in the decades since), but it is, by far, the best of the lot.