“In the Betty Boop short film "Snow White”, Koko the Clown (voiced by Cab Calloway) sings “St. James Infirmary Blues” when he believes Betty Boop is dead. Cab Calloway’s voice is unique and specially eerie for this song. Koko’s dancing during the “St. James” number is rotoscoped from footage of Calloway.“
The year is 1933. It’s a short, two minute-ish scene from Betty Boop's Snow White from the Fleischer Studios. Max Fleischer invented the rotoscope process. Roland Crandall was the animator of the film. Cab Calloway was filmed singing “St. James Infirmary Blues,” and rotoscoped, transforming into Koko the Clown.