reporter: when she s not playing mommy happy birthday to you reporter: she s center stage, performing all 18 number one singles night after night. this is my quick change room. the quick change room. just sent this in from paris. we have all different designer. he sent this beautiful dress in. no reveal. reporter: you can t see that. only people in the show like mariah and myself know the set list. don t try to ruin our show. thank you. i m coming to your show. i m screaming. mariah! i m michael strahan in las vegas. i feel like he s going to make a cameo in her show. i wouldn t be a surprised. he makes a cameo in everybody s show. he ll be here next week.