From Maren Morris to Sugarland! All the Surprise Guests on Taylor Swift's Reputation Stadium Tour
Swift also invited out Aussie pop star Troye Sivan at her second Pasadena show.
What They Sang: "My My My!"
One Direction alum Niall Horan surprised fans at Swift's first Wembley Stadium show in London, June 22.
What They Sang: "Slow Hands"
Take That star Robbie Williams hit the Wembley Stadium stage on June 23, at Swift's second London set.
What They Sang: "Angels"
TIM MCGRAW & FAITH HILL
Hometown girl Maren Morris (she was raised in nearby Arlington) joined Swift onstage for her Oct. 5 show in Dallas, Texas.
"VOCALS MAREN," the popstar captioned a video of their performance. "Maren is from Arlington and judging from the deafening screeches of joy from the crowd, they are proud of her. So so grateful this happened."