Celebrities that were big in the 1930s appeared in Betty Boop cartoons and would often perform their hit songs which were popular in the 1920s-1930s.

Ethel Merman 

Ethel Merman appeared in Time on My Hands, where she sung the cartoon's title theme, and in You Try Somebody Else, where she performed "Sweetheart".

Rudy Vallée 

Rudy Vallée appeared in Betty Co-Ed, Kitty From Kansas City, Musical Justice, Rudy Vallée Melodies and finally, in Poor Cinderella.

Cab Calloway 

Cab Calloway appeared in Minnie the Moocher, Snow White and The Old Man of the Mountain. He performed songs in all three cartoons.

Arthur Jarrett 

Arthur Jarrett appeared in Just One More Chance and Popular Melodies, where he performed "My Silent Love" and Betty Boop's theme song "Sweet Betty".

Maurice Chevalier 

Maurice Chevalier had a small cameo in Stopping the Show, where he tells Betty Boop to impersonate him and right now. Maurice was a fan of the series, his hit song "Hello Beautiful" was featured in My Wife's Gone to the Country and Bimbo's Express in 1931.

Irene Bordoni 

Irene Bordoni performs the title song in Just a Gigolo. Betty introduces her by saying "Let's give little Irene a great big hand!"