Allan Jones was intended for Ted Barker, but the role went to James Stewart.

Eleanor Powell singing voice was dubbed by Marjorie Lane.

Cole Porter picked James Stewart for the male lead and later said he sang "Easy to Love" as well as any professional singer. A dubbing track was prepared with baritone Jack Owens, but it was decided that Stewart's tenor voice was perfect for the song. In That's Entertainment!, Stewart said, "The song had become a huge hit, even my singing wouldn't hurt it."

Geraldine Robertson played Chorine (uncredited). She landed the part as a result of being crowned Queen of the Centennial at the Texas State Fair in 1936, crowned by Ginger Rogers, and part of the prize for winning was a screen test with MGM.

According to the biography "Beyond the Rainbow", this film was at one point to have included a role for Judy Garland.

Some cast members in studio records/casting call lists did not appear or were not identifiable in the movie. These were (with their character names): Charles Lane (Stage manager), Billy Watson (Newsboy) and Fuzzy Knight (Pianist).

The cop in Central Park (played by Reginald Gardiner) spoofs conductor Leopold Stokowski and incorporates his long hair and dramatic gestures.

The dress that Virginia Bruce throws on the floor and refuses to appear in is the same dress worn by Jeanette MacDonald in San Francisco, a few months earlier.

The only appearance by James Stewart in a musical film.

The submarine shown entering New York harbor at the beginning of the film is USS Pike (SS-173).