When famed opera singer Luciano Pavarotti fell ill and couldn't sing at the 40th Grammy Awards, Aretha stepped in and sang for him. BUT, did she cop out and sing one of her own songs? NO!! She sang the aria that Pavarotti was supposed to sing, "Nessum Dorma." And, as usual, SHE KILLED IT. I mean, they already had the choir there, so why not?