The Singing Nun.

Belgian nun Sister Ann is sent to another order where she's at first committed to helping troubled souls, like Nichole and little Dominic. When Father Clementi hears Sister Ann's uplifting singing style, he takes her to a talent contest. Sister Ann is signed to a record deal and everyone is listening to her lighthearted songs. She is unprepared for her newfound fame (like appearing on The Ed Sullivan Show) and unwanted side effects, including a wrongful attraction to an old friend.