Lopez introduced Emme using the gender neutral pronouns they and them.
“So this is a very special occasion. They are very, very busy. Booked. And pricey,” Lopez went on to say. “They cost me when they come out. But they’re worth every single penny because they’re my favorite duet partner of all time.”
Emme then appeared on stage, carrying a rainbow microphone to sing Christina Perri’s hit, “A Thousand Years.”
Lopez shares Emme and twin brother Max with her ex husband, singer and actor Marc Anthony.
CNN has reached out to Lopez for comment.