Cab Calloway voiced Koko the Clown, singing “St. James Infirmary Blues” in Betty Boop’s animated short ”Snow White” (1933)
Betty Boop’s Halloween Party (1933) - by Max Fleischer

Mae Questel c. 1938
In addition to her signature voices of Betty Boop and Olive Oyl, Questel also provided the voice of Little Audrey and Casper, the Friendly Ghost in their respective animated shorts
Betty Boop’s Halloween Party (1933 - by Max Fleischer
Betty Boop in There’s Something About A Soldier (1934) - by Max Fleischer
Betty Boop in Max Fleischer’s Poor Cinderella - 1934