Mindful of the American aversion to dubbed foreign films, the production team decided that the shooting would be exclusively made in English language despite the accent of the actors. Consequently the English looping coincided so well with the lip movements of the actors that no one in the U.S. noticed the film was dubbed.
Despite a prominent co-starring billing, Camille Keaton, who plays the title character of Solange, has no dialogue throughout the film.
When asked how she was cast for this film, Camille Keaton said during an interview, "Well, I met this gentleman on a flight, and he started talking to me. He told me he was an Italian director, and his name was Massimo Dallamano. I then went into Italian director Zefirelli's office, to take some photographs. I later received a call from the director on the flight who had done a film called The Portrait Of Dorian Gray. He had seen the photographs I had taken before, and he said he wanted me to be the main character Solange in the film, What Have You Done To Solange? He had directed plenty of Giallo films. Ya know, it was just luck. I'm still proud of the film and its huge success.
70mm blow-up version released in Spain.