When Nichole (Noëlle Adam) had to slap Jennifer (Gillian Hills) in a scene, Jennifer kept anticipating the slap and turning her head prematurely, so on one final attempt Nichole went for it and caught her with a real hard slap not giving her a chance to pre-empt the slap.
The soundtrack album was the U.K.'s first long-playing record devoted to a single movie score.
Gillian Hills said Adam Faith was so normal and natural and under-playing everything, while she was overdoing everything "like a fourteen-year-old Shelley Winters".
Gillian Hills was fourteen-years-old when making the movie. Adam Faith eighteen, and Oliver Reed twenty.
When making this movie, Gillian Hills was fourteen, the same age as Sue Lyon around the same time in Stanley Kubrick's Lolita (1962). A decade later, Hills would play one of Alex's two conquests, Alex portrayed by Malcolm McDowell, in Kubrick's A Clockwork Orange (1971) (the famous sped-up sex scene).