Taylor Swift's best 1989 world tour surprise guests

Brit dance queen Charli XCX joined Taylor on stage for night two in Toronto on Oct. 3, where the two performed "Boom Clap."
Photo: Getty Images

Keith Urban joined Taylor for a pyro-tastic two songs during her first stop in Toronto.
Photo: Getty Images

The world went wild over news that Rolling Stone Mick Jagger popped up to duet one of his band's greatest hits, 'Satisfaction.'
Photo: © Getty Images

Taylor and Leona Lewis sang 'Bleeding Love' to a sold-out crowd in Nashville on Sept. 26, the same night that Mick Jagger took the stage.
Photo: © Getty Images

Not wanting to miss out on the action, Steven Tyler joined the pop star at a Nashville show to sing 'I Don't Want to Miss a Thing."
Photo: © Getty Images

Taylor brought Wiz Khalifa on stage to sing 'See You Again' in Houston on Sept. 9.
Photo: © Getty Images

Cara Delevingne and Mariska Hargitay:
"Couldn't even contain my happiness because @caradelevingne and @therealmariskahargitay surprised the crowd tonight. #1989TourPhilly".
Photo: © Instagram

St. Vincent and Beck:
"St. Vincent casually slaying that guitar solo while pyro goes off in the background. Beck and I having a dance party. I don't know how to process any of the events of tonight."
Photo: © Getty Images

Uzo Aduba:
"I'm so blown away by the multi-talented Uzo Aduba and how she smashed "White Horse" tonight. And also by how incredibly down to earth and wonderfully kind she is."
Photo: © Instagram

Taylor is usually surrounded by her girls, but in LA, the singer welcomed actors Matt LeBlanc and Chris Rock, and model Sean O'Pry. Photo © Getty Images

Julia Roberts and Joan Baez:
"Tonight Joan Baez and Julia Roberts danced it out to 'Style'. These two women are my heroes. What an honor."
Photo: © Instagram

Little Mix:
"Little Mix smashed it in front of 50,000 screaming fans tonight! #1989tourSantaClara."
Photo: © Instagram

Fifth Harmony:
"So stoked this pic exists because this was SO MUCH FUN @FifthHarmony".
Photo: © Instagram

Ciara:
"Can't even describe how happy I was when this was taken. Thank you again @Ciara for being so magical."
Photo: © Instagram

Fetty Wap:
"Unable to find my chill because of @fettywap1738 singing 'Trap Queen' for 60,000 people in Seattle. Amazing night!!"
Photo: © Instagram

Ciara and Russell Wilson:
"That Seattle crowd went ABSOLUTELY INSANE when @ciara and @dangerusswilson walked out!! I LOVED TONIGHT."
Photo: © Instagram

Nico and Vinz:
"I am OBSESSED with @nicoandvinz and so was that Vancouver stadium crowd!! They are absolutely dynamic performers, the most down to earth guys, and Am I Wrong is such a brilliant song. SO HAPPY TONIGHT and so in awe of great artists like this."
Photo: © Instagram

Walk The Moon:
"Thanks @WALKTHEMOONband for surprising the Boston crowd with 'Shut Up and Dance'!!! 60,000 person dance party."
Photo: © Instagram

Serayah:
"Later on, when @serayah slayed it on stage singing 'Style' with me at Soldier Field in Chicago...."
Photo: © Instagram

Jason Derulo:
"I got to sing my fav summer JAM 'Want To Want Me' with @jasonderulo in DC- I'm also loving his new single 'Cheyenne'!"
Photo: © Instagram

Lorde:
"When your friend flies across the world to surprise your crowd with 'Royals' because she's a wondrous angel. @lordemusic."
Photo: © Instagram

Candice Swanepoel, Lily Aldridge, Martha Hunt, Uzo Aduba, Karlie Kloss, Behati Prinsloo and Gigi Hadid:
"I ADORE THESE GIRLS. @angelcandices @lilyaldridge @marhunt @uzoaduba @karliekloss @behatiprinsloo @gigihadid."
Photo: © Instagram

Nick Jonas:
"Last night the incredible @nickjonas sang 'Jealous' and 60,000 people sang it with us/screamed uncontrollably."
Photo: © Instagram

Hailee Steinfeld, Lily Aldridge, Gigi Hadid, Lena Dunham:
"The Trinity, Frostbyte, Slay-Z, and Lucky Fiori brought the Bad Blood video to life tonight at #1989TourEastRutherford."
Photo: © Instagram

US Women's football team:
"Got to welcome the U.S. Women's Soccer Team home after their World Cup Victory- I LOVE THEM AND THEY ARE THE NICEST."
Photo: © Instagram