Goodbye Charlie (1964)

Very much a product of its time with its swingin' sixties, playboy aura. Hollywood writer Charlie Sorel is murdered by film producer Leopold Sartori (Walter Matthau) when he catches Charlie with his wife. But the playboy is reincarnated as a woman (Debbie Reynolds)--much to the confusion of the male Charlie's best friend, George (Tony Curtis). And the female Charlie decides to see how the other half lives, loves, and gets revenge. Based on the play by George Axelrod.