What song is performed by Diana and Gabe in Act 1, Scene 10? What does Gabe encourage Diana to do?

Diana sings of a dreamy imagined dance with Gabe, who appears in a tuxedo and dances with her to a lightly textured waltz tune, "I Dreamed a Dance," eventually influencing her to say, "I'll die to dance with..." In response, he calls her to join him in a place where there's no pain ("There's a World," a tender ballad) and where they can be free.