Justin Bieber made a surprise appearance Tuesday at the first of Taylor Swift‘s four sold-out shows at Staples Center.

“Who wants to see my friend Justin?,” Swift asked the nearly 15,000 fans in attendance.

The “Fearless” singer not only performed all her hits and then some last night, but she also squeezed in some Jason Mraz, Gwen Stefani and the Beach Boys.

Swift later tweeted, “You think you’ve heard LOUD screaming in your life.. Then @justinbieber comes out and does a surprise song during your show. Woah. Unreal.”

Bieber responded to the country-pop singer, tweeting, “@taylorswift13 we should do that more often. :) great show! #muchlove.”