Les Brown and His Band of Renown play while an impossibly young Doris Day sings the title song in this soundie.
It's one of thousands of soundies, short musical films created from the late 1930s through the middle of the 1940s to play on a device known as a Mills Panoram. You may think of them as video jukeboxes, or precursors to music videos. You could find them in bars, and a dime in the machine would bring you one of ten songs.
And that's how Miss Day started out in the movies in 1941, almost eight years before she was 'discovered' in 1948. This lively swing number has her and the band in military uniform belting out the tune, showing what she could do. Eventually, the big producers would figure it out.