Afterward ("Good Morning"), Don, Kathy, and Cosmo come up with the idea to turn "The Dueling Cavalier" into a musical called "The Dancing Cavalier," complete with a modern musical number and backstory. The three are disheartened when they realize Lina's terrible voice remains a problem. Still, Cosmo, inspired by a scene in "The Dueling Cavalier" where Lina's voice was out of sync, suggests that they dub Lina's voice with Kathy's ("Singin' In the Rain"). After hearing Don and Cosmo pitch the idea ("Broadway Melody"), R.F. approves but tells them not to inform Lina that Kathy is doing the dubbing.("Would You"). Having learned the truth, an infuriated Lina barges in on a dubbing session, and becomes even angrier when she is told that Don and Kathy are in love and intend to marry, and that R.F. intends to give Kathy a screen credit and a big publicity buildup. Lina threatens to sue R.F. unless he makes sure no one ever hears of Kathy and that she keeps dubbing for the rest of her career. R.F. reluctantly agrees because of a clause in Lina's contract which holds the studio responsible for positive media coverage.