Swift joined the singer for a duet version of Lopez’ "Jenny From the Block” at the Staples Center in Los Angeles. Nelly, Ellie Goulding, and Tegan and Sara are among the other guests that Swift has invited to surprise her fans.
As she was introducing J.Lo, Swift said the tune was her “hairbrush song.”
“You just blast it in your room and sing in front of your mirror into a hairbrush,” she explained to the crowd. “You had that one favorite song that was your favorite to dance to …”
Here’s the video. Grab your hairbrush: