What Became of Jack and Jill? is a 1972 British horror film directed by Bill Bain and starring Mona Washbourne, Paul Nicholas, and Vanessa Howard. It was part of an abandoned attempt by Amicus Pictures to differentiate itself with Hammer Studios by breaking into the grindhouse market. Studio executives were ultimately too disturbed by the final product to release it under the Amicus name, and they sold the film to 20th Century Fox.

Paul Nicholas is an English actor and singer, best known for his work in the 1983 BBC sitcom Just Good Friends. The show won a BAFTA and Nicholas was nominated for best comedy performance.