The Strange Type (1963)

Original title: Uno strano tipo

Peppino, a slow-witted local villager of the Italian resort town of Amalfi, is bribed to impersonate famed rock and roll star Adriano Celentano for autographs and personal appearances. While Celentano tries to romance Emanuela Mazzolani, the daughter of a well-to-do resident who dissaproves of the union between his daughter and the man he thinks of as a "punk", Peppino, unaware of the true nature of his job to impersonate Celentano, tries to deal with his girlfriend's newborn baby which gets switched around between him and Celentano.