Siebenmal in der Woche (1957)

Roberto Ricci is an international singing star. To reduce the pressure on him from female fans, his agent arranges a sham marriage through an agency. The girl in question, Loretta, has to pretend to have no interest in music and dancing, and she meets him dressed in the dowdiest and frumpiest clothing possible. But surprise surprise, things develop, and they discover that they are really true soulmates.