Taylor Swift revealed even more behind-the-scenes secrets of her Eras Tour in the latest installment of her new docuseries. Episode 4 featured an appearance by Swift's fiancé, Travis Kelce, who made a surprise cameo during a June 2024 stop on the European leg of The Eras Tour. The episode chronicled how his stage debut came together during his summer break from the NFL. "The way that he just comes to life when the lights are the brightest, people talk about that all the time with him," Swift, 36, said of Kelce, also 36. "They're like, 'The moment's never too big for Travis. The lights are never too bright for Travis.'" Episodes 3 and 4 of Taylor Swift: The End of an Era debuted on Disney+ on Friday, December 19, one week after the first two episodes dropped on the streaming services. In the premiere, Swift broke down just how difficult it was to add songs from The Tortured Poets Department to the setlist while still trying to keep the album from leaking ahead of its release. "When we had done the first half of the tour, what the fans didn't know at the time was that I was writing a brand-new album, The Tortured Poets Department, and in the middle of me releasing the album, we had to be all hands on deck, creating a brand new era to put into the show to represent that album," she explained in episode 2. "We built this top-secret rehearsal facility for us to lock in the setlist. ... And then we put together all new choreography. Learning choreography, all just hearing it in our heads, because they can't play the music on speakers because it's not out yet." Why Taylor Swift Is Living a 'Lighter' and 'More Unfiltered Life' Keep scrolling to read the biggest revelations from episodes 3 and 4 of Taylor Swift: The End of an Era, which are now streaming on Disney+. The two-part finale will premiere Tuesday, December 23. Taylor Swift Was 'Always Planning' Her Future Tours Taylor's mom, Andrea Swift, recalled her daughter having huge ambition starting in her childhood. "Very early on, she just knew she was gonna have to work hard," Andrea, 67, explained in episode 3. "I mean, it just depends on how far back we wanna go. But it escalated from school play, theater group, karaoke nights, calling around to festivals and amusement parks to see if there was a spot for a little kid with a guitar and a couple of speakers. ... And she, from a very early age, always knew exactly how she wanted things to be. And she was always planning what her headline tour would be like." Andrea noted that Taylor was always focused on her art rather than the perks that came with it, saying, "You know, I never heard her say the word 'fame' or 'money.' It was always just about the opportunity to go sing her songs and have everybody else singing those same words back." Making the New 'Reputation' Bodysuit Throughout the tour, Taylor wore tons of different outfits across each era but famously only had one look for Reputation - until she debuted a new bodysuit when the tour returned to the U.S. in October 2024. Her longtime stylist, Joseph Cassell, explained in episode 3 that part of the reason it never changed was because they ran out of the fabric that was used for the first one. When Cassell initially presented Taylor with the new one, it didn't fit quite right, but after seamstress Diana Aghajanyan made adjustments, the pop star was obsessed. "It's now my favorite," Taylor quipped after trying it on. "I didn't see this coming. I'm shocked." An 'Eras' Vocalist Battled Cancer During the Tour In episode 3, background vocalist Jeslyn Gorman revealed that she was diagnosed with breast cancer after the tour began. According to Taylor, Gorman's diagnosis was the "first blow" the tour "family" had experienced together. Gorman took six months off for chemotherapy and surgery, losing about 75 percent of her hair in the process. She ultimately returned to the tour after finishing radiation - and came back so quickly that her coworkers were inspired by her strength. "I cannot believe that she was back in a few months," Taylor marveled. "The will to come back and do the hardest show ever, none of us could believe it. I still can't." Taylor Swift's 'Eras Tour' Costume Changes Were Insanely Complicated "Every outfit change is about a minute and 15 [seconds] or less," dresser Jestina O'Dell explained in episode 3. "Our fastest quick-change though is 39 seconds with her in the room." Taylor's mom, Andrea, added, "It is like watching a NASCAR race." Under the stage, there were four quick-change booths constructed on different levels, and Cassell noted there were 20 quick-changes in the show. "There were moments where I thought, 'I don't know if these costume changes are gonna happen in time,'" Taylor admitted. "I'm only off the stage for a maximum of two minutes at a time. ... You have no idea the panic of worrying you're not gonna be dressed in time for the song to start." She recalled one moment where she tripped over her Evermore dress and busted her knee before l