The sight of Taylor Swift at Kansas City Chiefs games became a familiar one last season, with the pop megastar in attendance to support her boyfriend, tight end Travis Kelce. Ms. Swift went to 13 of the Chiefs games, including both the regular season and playoffs, and was there for the team’s Super Bowl victory over the San Francisco 49ers.

She even joined him on the field after the game. So naturally many Swifties wondered when Mr. Kelce might return the favor and join Ms.

Swift during her worldwide Eras Tour—and perhaps even join her on stage just as she had joined him on the field. This weekend they had their answer. The football player made his onstage debut at Wembley Stadium in London on Sunday.

But Mr. Kelce didn’t just come on stage for a token appearance, wave to the crowd, and head backstage; he actually took part in Ms. Swift’s performance.

Mr. Kelce, dressed up in a suit and top hat, just like Ms. Swift’s backup dancers, and came on stage after the singer, in character, fell to the ground while performing “The Smallest Man Who Ever Lived.

” Then, the 6-foot-5, 250-pound Mr. Kelce picked up the singer and carried her to a red couch on stage, while he and the two backup dancers revived Ms. Swift and got her back to her feet.

Mr. Kelce then did a little jig to try and cajole Ms. Swift to perform, which seemed to work.

Kelce continued the act by swabbing Ms. Swift’s face with a makeup brush, which then led to her reanimation and performance of “I Can .