Ángela Molina pulled out just ten days before filming started because she wanted some changes made to the screenplay and these never happened. She and her sister, Mónica Molina, were going to play Lulú in her different life stages.
Even though he wanted actresses to play young and adult Lulú, when Francesca Neri auditioned, Bigas Luna was so amazed that he decided to have her play both versions.
In an interview, Bigas Luna recalled the episode when Francesca Neri, due to script requirements, was forced to shave her vulva and burst into tears before shooting one of the film's most scabrous scenes. He had to go and cheer her up and Neri, says Bigas Luna, "opened her bathrobe and shot her sex in my eyes and said to me, crying: 'Bigas, I'm sick, I look ugly, hideous'".
Luis García Berlanga was offered the chance to direct the movie but refused, and actually recommended producer Andrés Vicente Gómez to offer it to Bigas Luna because he thought it was a great fit for him.