Rivera was 33.
She and Riley were original cast members of the hit Fox musical series and close friends.
Guest host Lil Rel Howery introduced Riley’s performance.
“I’m ready to fight/ I’m ready to see/ What’s on the other side/ I’m ready to cry and just let it be/ I just gotta let it be,” Riley sang.
Rivera was the subject of an exhaustive search for days after she went missing from Lake Piru in Ventura County, California, while boating with her son, Josey.
Authorities said her son told them they went swimming, but his mother didn’t get back on the boat.