Paramore have spent the last month opening for Taylor Swift on the UK/European leg of “The Eras Tour.” On the second night of the tour’s run at London’s Wembley Stadium on Saturday night, Paramore’s Hayley Williams pulled doubled double as she also made a guest appearance during’s Swift main set to perform their version of “Castles Crumbling” live for the first time.

Williams and Swift both expressed admiration for each other during the performance. “I love you so much. You’re so good, it’s crazy. I cannot believe that I get to be on a tour with Hayley. I can’t believe she’s ever talked to my once,” Swift remarked. Williams responded, “You’re my longest music friend. Thank you. I love you.”

Williams and Swift’s relationship dates back to their years as teenage songwriters in Nashville. Their version of “Castles Crumbling” appeared on  Speak Now (Taylor’s Version), which was released last year.

The European leg of “The Eras Tour” runs through late August, after which Swift will kick off one last leg of stadium shows in North America. Fans can find last-minute tickets here.

Hayley Williams joined Taylor Swift to perform “Castles Crumbling” during tonight’s “Eras Tour” concert at London’s Wembley Stadium. pic.twitter.com/y1PlWLraeB

— CONSEQUENCE (@consequence) June 22, 2024

Hayley and Taylor performing castles crumbling at the eras tour!!!! pic.twitter.com/eTeJFjjDFz

— hinna williams (@IDLEW0RSHlP) June 22, 2024