Los Angeles can check off seeing Sabrina Carpenter sing with Christina Aguilera from their Christmas list. On Friday night’s Short n’ Sweet concert at Crypto.com Arena, Aguilera joined Carpenter in singing “Ain’t No Other Man†and “What a Girl Wants,†probably as a consolidation prize for stepping foot in a place called Crypto.com Arena. Aguilera popped out on stage wearing knee-high boots almost as sparkly and tall as Carpenter, and the two began to belt out the tracks. Last month, the two recorded a duet of “What a Girl Wants†for Spotify; it was a huge milestone for Carpenter, as she’s previously said Aguilera was the first artist she fell in love with. And after scoring 6 Grammy nominations last week, it’s just proof that it’s Miss Polly Pocket’s world and we’re just living in it.