Taylor Swift and Robbie Williams perform on stage during the Reputation Stadium Tour at Wembley Stadium on June 23, 2018 in London, England.

The latest famous guest to take the stage on Taylor Swift's Reputation World Tour is Robbie Williams.

To the delight of the crowd, the pair sang Williams' hit "Angels" together at London's Wembley Stadium Saturday night (June 23). Williams even wore a Taylor Swift T-shirt for the occasion, which started off with Swift on the piano before the British pop star popped up onto the stage.

"OMFG ROBBIE WILLIAMS JUST JOINED TAYLOR SWIFT ON STAGE AND WEMBLEY HAS GONE MENTAL!" one concertgoer wrote on Twitter.

At previous shows on this tour, Swift has invited Shawn Mendes, Selena Gomez and Troye Sivan, and Niall Horan to the stage for surprise performances.

Watch clips of Swift and Williams singing together below -- including one shared by Swift herself on Sunday.



