Much of the footage of the Windmill dancers in rehearsal was originally shot for Primitive London (1965), but not used.
Pauline Collins' first film, a fact she delighted in bringing up with journalists when making Shirley Valentine (1989), if they hadn't done their research.
Originally intended as a straightforward record of the last nude review presented at the Windmill Theatre, the routines were woven into a crime story.
Renee Houston, Derek Bond, Harry Fowler and Howard Marion-Crawford (as Howard Marion Crawford) all receive 'guest stars' credits.
Actress/singer Dana Gillespie's first role. She was 16 and one of the few female participants who didn't strip naked. She appeared briefly as a singer during a party sequence. During a 2020 interview, she said, "The song I sang in SECRETS OF A WINDMILL GIRL was my first song. I remember the publisher, a man called Hal Schaffer, he's probably dead now, he seemed ancient to me then when I was 16. He gave me a flat fee of £25. Nowadays I would never ever do that, I would stick with the royalties."