While Brian De Palma was making Carrie ( as a part of his Alfred Hitchcock imitation films ), Alfred Hitchcock himself was making his last picture Family Plot, where he used the composer from Steven Spielberg's Jaws John Williams for the score. De Palma, probably knowing Williams through Spielberg, decided to mess around with Hitchcock himself, making a sort of yet another Carrie ( a film about people with superpowers ) but this time hiring John Williams himself for the score. And weirdly enough ( while Spielberg was finishing Close Encounters and starting 1941 where his camera sexually obsessed over De Palma's GF at the time Nancy Allen ) De Palma hires Spielberg's girlfriend at the time Amy Irving for the lead role.