Matt LeBlanc, Chris Rock and Sean O'Pry
For Swift's first L.A. show, the Friends alum, comedian and "Blank Space" star were the show's guests.
John Legend
Wearing a gorgeous sparkly gown, Taylor helped Legend perform "All of Me," the love song he wrote about his wife.
Andy Grammer
Honey, she's good! Andy Grammer performed his new hit song when Taylor hit the Windy City.
Jason Derulo
During her Washington, D.C. show, a shirtless Derulo surprised fans with a sexy performance of "Want to Want Me."
The Weeknd
For one of her New Jersey shows, Taylor's special guest brought the house down with the hit song "Can't Feel My Face."
Uzo Aduba
The Orange Is the New Black star joined Swift onstage to duet to her hit "White Horse."
Nick Jonas
Oh, how times have changed! Nick Jonas joined Swift onstage for a "Jealous" duet years after she was the celeb cameo on the Jonas Brothers tour.
Mariska Hargitay & Cara Delevingne
Olivia's namesake takes the stage! The Law & Order: SVU star paid a visit to Taylor's show with the Paper Towns actress.
Mary J. Blige
The R&B singer was brought onstage in Los Angeles to perform her 2001 hit "Family Affair."
Julia Roberts & Joan Baez
Two new members joined Taylor's squad during her Santa Clara stop as the actress and folk singer danced it out to "Style."
Kobe Bryant
The NBA supertar surprised Taylor with a banner that celebrated her record breaking run of sold-out shows at the Staples Center.
Serayah
The Empire star and one of Taylor's "Bad Blood" badasses hit the stage during her Chicago show.
Russell Wilson & Ciara
The Seattle Seahawks quarterback and his leading lady showed they were ecstatic to be part of Taylor's cameo club.
Sam Hunt
Taylor brought out the country crooner in Chicago so they could duet to his single "Take Your Time."
The Model Squad
Candice Swanepoel, Behati Prinsloo and more of Taylor's model pals joined Orange Is the New Black's Uzo Aduba onstage at MetLife Stadium in New Jersey.
Fifth Harmony
Swift matched the ladies in blue as they performed their hit song "Worth It."
Gigi Hadid & Martha Hunt
Taylor's model BFFs had no problem rocking the catwalk during her Detroit concert.
Ryan Tedder
Taylor invited the One Republic frontman to duet to the anthem "Counting Stars."