Taylor Swift and Jennifer Lopez brought a little Bronx to Los Angeles. J.Lo was the "22" singer's surprise guest performer during the last stop of her Red Tour at L.A.'s Staple Center. The two dueted on Lopez's hit, "Jenny From the Block." Swift introduced Lopez by talking about when she was a little girl. "You know how you have your favorite song that you just play over and over and over again," she said. "You just blast it in your room and you'd sing in front of your mirror into a hairbrush, right? You have that one favorite song. It was your favorite song to dance to. Los Angeles, this is my hairbrush song."