The Man on the Flying Trapeze (1954)

Sort of a cartoon version of "All About Eve" or people-using-people themes. It opens with a man singing the title song, accompanied by a pianist, a trumpeter and a trombonist. A flashback to the story of Fifi who leaves Waldo for Alonzo, and then leaves Alonzo for the circus owner. Back in the present it is shown that all three men are the musicians and they are almost run down by a limousine, occupied by Fifi, now a stage star.