Croon Crazy(1933)

An Oil-can-Harry radio announcer presents Cubby Bear the Crooner as the star of his own radio program over station R-K-O and, while Cubby is crooning away, Slick also advises that Kitty Schmidt (Kate Smith), Cal Jolson (Al Jolson)and Sol Rightman (Paul Whiteman) will be Cubby's guest stars. Then a 100-year-old Western-Union 'boy' delivers a telegram informing that none of the guests will appear. So Cubby has to do the whole program by himself. Cubby comes through.