Cab Calloway and the Cabaliers sing the song, while the orchestra plays the lively tune.
Soundies were short films, about three minutes in length. The were meant to be played on a machine called a Mills Panoram, a video jukebox that was typically to be found in bars, lounges, and similar venues. You put a dime in and got a performance from the ten on the machine. The movies would be changed weekly, and from 1940 through 1946, Mills and other companies produced more than two thousand soundies.
When soundies came in, Vitagraph, which had been producing musical shorts since 1926, stopped. It doesn't seem like a coincidence.