Thanks for the Boogie Ride

Gene Krupa and his band plays the title song with Anita O'Day singing in this soundie. Or do they?

Soundies were short films, usually about three minutes in length. They were played on a machine called the Mills Panoram, a sort of video jukebox you might find in bars, diners, and similar venues. Between 1940 and 1946, Mills and a few others produced more than two thousand of them.

Because of the way they were produced, the soundtrack was almost invariably played while the performers mimed their actions. That's clearly what happens here. Not only do we see Miss O'Day dancing without her mouth movie while singing the song, not only is Roy Eldredge not putting any wind into his horn, but Krupa is muting his cymbals while pretending to strike them.