British pop star Robbie Williams has developed a "proper crush" on Taylor Swift after surprising fans by joining the Shake It Off hitmaker onstage in London.
Swift took over Wembley Stadium for the second night in a row on Saturday (23Jun18), when she settled down at a piano and began covering Robbie's classic hit Angels.
However, she didn't perform the 1997 tune alone as the former Take That star then ran out onstage unannounced and joined in, stunning fans as they erupted into huge applause and cheers.
Robbie, who even sported a T-shirt from Taylor's Reputation Stadium Tour merchandise line, later took to Twitter to share his joy at the experience.
"What an honour to sing with you tonight @taylorswift13 I've got a proper crush," the married star gushed, as he shared a photo of the pair onstage. "THANK YOU THANK YOU THANK YOU (sic)".
Robbie's unexpected appearance came a day after Taylor introduced One Direction star Niall Horan to the stage to treat fans to a performance of his solo hit Slow Hands.
Bringing him out on Friday for her first headlining Wembley Stadium show, Taylor told the audience, "I was wondering if a crowd this incredible would be up for a surprise performance, what do you think about that?
"They say when you're first starting out at something and you want to learn, learn from somebody who's done it before, so I decided to call up somebody who's played Wembley bunches of times. London, would you be excited if I told you Niall was here to play for you?!"
Niall and Robbie are the latest special guests to share the stage with Taylor on her current trek - she previously invited pop pals Shawn Mendes, Selena Gomez, and Troye Sivan to perform duets with her on the Reputation Stadium Tour, which started in May (18).
The London dates wrapped up her six-stop European leg. She will now head back to North America with her support acts Camila Cabello and Charli XCX to continue the shows in Louisville, Kentucky on 30 June (18).