Watch Taylor Swift Bring Out Shawn Mendes at Rose Bowl Concert

Singers perform Mendes' 2017 hit "There's Nothing Holdin' Me Back" in Pasadena

Taylor Swift brought out surprise guest Shawn Mendes to perform "There's Nothing Holdin' Me Back" during Swift's Rose Bowl concert Friday.

Taylor Swift brought out surprise guest Shawn Mendes Friday night during her concert at Pasadena, California's Rose Bowl, where the singers performed Mendes' 2017 hit "There's Nothing Holdin' Me Back."

Swift handled the opening verse of the Illuminate track by herself before welcoming Mendes to the stage. "Come on out, Shawn," Swift said.

The duet wasn't a complete surprise to Swift devotees: Earlier in the day, Swift posted pre-concert footage on social media of her and Mendes rehearsing the song. The performance came hours after Mendes unveiled a new song titled "Where Were You in the Morning?"

Swift has also frequently recruited her opening acts Camila Cabello and Charli XCX to perform "Shake It Off" with her onstage.

The Rose Bowl concert marked just the fourth show of Swift's acclaimed Reputation Stadium Tour; she'll return to Pasadena, California Saturday night for the second of two shows at the stadium.