Taylor Swift and Andy Grammer Keep Their Heads Up in Nashville

Go see Taylor Swift in concert this summer and you never know who might pop up on stage.

Throughout her Speak Now tour, Swift has surprised fans by singing duets with Justin Bieber and Nicki Minaj and, most recently, Tim McGraw, Kenny Chesney and Andy Grammer! All three joined the young icon for a show in Nashville over the weekend.

Below, you can watch Taylor introduce Grammer to the crowd and then join him for a rendition of "Keep Your Head Up," a song Swift says she listens to any time she's feeling down.

Andy Grammer & Taylor Swift - "Keep Your Head Up"