Taylor Swift and Selena Gomez at the Madison Square Garden

Fans who attended Taylor Swift's concert last Tuesday surely got the best surprise of the night when Selena Gomez appeared on stage! Taylor introduced Selena as her best friend for four years now (and counting). They did a duet of Selena's "Who Says". Here's a photo from Getty Images:

Photo by Getty Images

Posted in: Hollywood,Photos and Pictures,Selena Gomez,Taylor Swift