The Shake It Off singer continued to stun her fans with unannounced onstage star appearances in Toronto, Canada, where she invited the Australian country star to join her and perform his tracks John Cougar, John Deere, John 3:16 and Somebody Like You.

"Hey @taylorswift13 - u killed it last nite (night) - thank u for the invite - ridiculous fun!!!!!!" Keith wrote on after the show, adding, "And Toronto? Love for days!!!!! Thank YOU too."

Taylor then invited Charlie XCX up onstage for a performance of Boom Clap during her second night at the Rogers Centre on Saturday (03Oct15).

"Thank u so much for having me in Toronto tonight @taylorswift13 it was fuuuun", Charli wrote on Twitter.

Keith and Charli join a long list of guest performers who have performed with Swift at stops during her 1989 World Tour, including Justin Timberlake, Mick Jagger, John Legend and Selena Gomez.