Definition: Typical romantic scene implying seduction but with the “wrong” partner. Clear idea that there is a casting mistake. Does not include torch songs about a romance turning wrong. But includes jealousy scenes. Includes romances performed by the "right" couple, but as a performance while they're fighting, so they're not technically partners while romancing ("So in love 1" in Kiss Me Kate).
Example: “Between You And Me” (Broadway Melody Of 1940); “The Way You Look Tonight (2)” (Swing Time)