Something in the Wind (1947)
Something in the Wind is a 1947 American musical comedy film directed by Irving Pichel and starring Deanna Durbin, Donald O'Connor, and John Dall. Based on a story by Fritz Rotter and Charles O'Neal, the film is about the grandson of a recently deceased millionaire who mistakes a beautiful female disc jockey for her aunt, who once dated his grandfather. This was O'Connor's first film after he returned from military service in World War II. The film includes the famous "I Love a Mystery" number performed by O'Connor.
More at Wikipedia.