Taylor Swift joined The Rolling Stones on stage during their concert in Chicago on Monday, June 3.
The 23-year-old singer sang "As Tears Go By" with front man Mick Jagger during the concert and the singer Tweeted about her experience. Video of their performance can be seen below.
"Filing this under 'never in my wildest dreams'.Thank you @RollingStones for inviting me to Chicago to sing with you," Swift wrote in one Tweet on June 4, with a photo of herself and Jagger performing attached.
"Filing this under 'friends forever'. @MickJagger," she wrote in another Tweet with a black and white photo of herself and Jagger.
"As Tears Go By" was one of the first original songs Jagger and Keith Richards wrote together. The song was initially released by singer Marianne Faithfull before The Rolling Stones recorded their own version.
Underwood sang "It's Only Rock n' Roll (But I Like It)" with the band at their concert at Toronto's Air Canada Centre on May 25, while Perry performed "Beast of Burden" with the legendary band at their Las Vegas concert on May 11.
The Rolling Stones are currently on their 50 & Counting tour, which will travel through cities across the United States and Canada. Their kickoff performance in Los Angeles featured a surprise performance from No Doubt's Gwen Stefani.
Check out video of Taylor Swift performing with The Rolling Stones below.