Tyler called Swift's concert an "epic show" and telling her she "sure was [understood] tonight" after she tweeted, "I feel like I'd be more understood if people knew 'I Don't Want to Miss a Thing' by Aerosmith is how most of my emotions sound in my head."
In addition to the rock icon, Alison Krauss came out to duet with Swift on her own country hit, "When You Say Nothing At All." "Breathtaking. Regal. Elegant. @AlisonKrauss singing 'When You Say Nothing At All.' So blown away by her grace," wrote on Twitter after the show.
Rounding out the special guest appearances was Kelsea Ballerini, an up-and-coming country singer who Swift calls her "little sister." The two sang Ballerini's debut single, "Love Me Like You Mean It."
Ballerini has long admired Swift, who has given her sage career advice in the past. During the People's Ones to Watch party, Kelsea told ET that Taylor told her to "always just be human and warm because people will always relate to that."
"She's just such a wonderful human and that shines thru her music," the 22-year-old singer adds. "She’s lovely and it’s awesome to have a mentor."