Taylor Swift's Eras Tour was full of iconic moments, but few surprises could top the night her then-boyfriend, Travis Kelce, made a cameo during one of her London shows. Swift, 36, opened up about Kelce's stage debut during episode 4 of her new docuseries, The End of an Era, which dropped on Disney+ Friday, December 19. She explained that she thought he would fit in during the Tortured Poets Department skit where she's picked up by dancers after "dying" on stage, but she wasn't sure whether he'd ever do it. "If there was ever a point to put Travis in the show, I think this would be the one," Swift recalled. "But obviously, I'm, like, never gonna suggest that, because that's like - you don't wanna scare people, you know?" The Grammy winner said she "can't remember" how the discussion started when Kelce, also 36, mentioned he would do a cameo. Taylor and Travis Share Intimate Phone Call in Docuseries: 'I Love You So Much' "I think we were just joking around about him doing it, like him going up there with Kam [Saunders], and it became very clear that he, like, wasn't joking," Swift recalled. "And I was like, 'Oh, wait, no, you would do that?' And he was like, 'Yeah, it would be hilarious.' I was like, 'If you're serious about this, I will send your measurements to wardrobe and they'll get you a tux. Like, are you serious?' And he was like, 'Put me in. I'm in.'" She went on to gush about how he "comes to life when the lights are the brightest," whether he's on the stage or the field. "People talk about that all the time with him. They're like, 'The moment's never too big for Travis. The lights are never too bright for Travis,'" Swift explained. "As a player he can, like, slow down time in the most stressful moments, and that's exactly what we saw on stage. He got out there and was the most charming, delightful performer you could ever be on the stage with. Like, his instincts, he's just so magically entertaining." "I can safely say that was the loudest it ever got on The Eras Tour," she added, recalling the moment Kelce appeared on stage at her June 23, 2024, concert at London's Wembley Stadium. Taylor Swift Calls Travis Kelce the 'Greatest Surprise of My Life' Taylor's mom, Andrea Swift, also weighed in on the moment and her future son-in-law, saying, "Travis Kelce brings a lot of happiness to a lot of fans." As Swifties may recall, Kelce joined Taylor during the Tortured Poets Department section of her Eras Tour setlist during one of her London shows last year. Wearing a tuxedo and top hat, he picked up Taylor and carried her to her red couch so she could begin the process of changing out of her voluminous white dress before singing "I Can Do It With a Broken Heart." Shortly after the concert, Kelce revealed on his "New Heights" podcast that he initially pitched a cameo appearance as a joke - but Taylor was into the idea. "I initially mentioned it to Tay," Travis told his brother, Jason Kelce, during a July 2024 episode. "I was like, 'How funny would it be if I just rolled out on one of the bikes during the 1989 era?'" Travis was surprised when Taylor then asked whether he would actually ever do something like that. Taylor Swift's Mom Gushes Over Travis Kelce in New 'Eras Tour' Doc Trailer "I was just like, 'What? I would love to do that, are you kidding me? I've seen the show enough - might as well put me to work here,'" he recalled. "And sure enough, she found the perfect part of the show for me to come in." He went on to joke that he was nervous about his role as the person who had to carry Taylor to the couch. "The one thing I told myself is, 'Do not drop the baby. Do not drop this. Do not drop Taylor on your way over [to] this damn couch,'" he quipped. "The golden rule was do not drop Taylor. Get her to the couch safely." Taylor and Travis announced their engagement in August after two years of dating, sharing the news via a joint Instagram post. "Your English teacher and your gym teacher are getting married," they wrote in the caption. The first four episodes of Taylor Swift: The End of an Era are streaming now on Disney+. Episodes 5 and 6 premiere Tuesday, December 23.