Chris Stapleton accepts the award for best country solo performance for "Traveller” at the 58th annual Grammy Awards on Monday, Feb. 15, 2016, in Los Angeles. (AP Photo)
Recording Academy CEO said Lauryn Hill, who was supposed to surprise the audience by performing with the Weeknd, said Hill showed up for dress rehearsal but didn't make it in time for the show. The academy never officially announced Hill was performing.
"She was invited by (the Weeknd)," Portnow said backstage.
Collaborative performances were one of the themes of the Grammys: Carrie Underwood sang with Sam Hunt; Ellie Goulding and Andra Day performed; and while Lovato, Legend, Luke Bryan and Tyrese sang with Lionel Richie to honor the icon.
Meghan Trainor, who was nominated for two Grammys last year for "All About That Bass," won best new artist.
"Thank you to the Grammys, I love you so much," said a teary-eyed Trainor, who also thanked her parents and Epic Records CEO L.A. Reid.
Other winners included D'Angelo, Kirk Franklin, Jason Isbell, Tony Bennett, the cast of Broadway's smash "Hamilton" and Jeff Bhasker.