Fans attending the Rolling Stones' concert in Chicago last night got a surprise when Taylor Swift walked onstage to perform a duet with rock legend Mick Jagger.
The band slowed down the pace of their 1965 hit As Tears Go By as the duo belted out the lyrics and then Jagger led Swift around the stage, twirling her repeatedly in slow dance movements along the way.
While Jagger, 69, noted that it had been awhile since the band hadn't performed the song -- one of the first he ever wrote with his 69-year-old band mate Keith Richards -- he said it was first performed by a lady so it was appropriate that Swift take the stage this time around.
After the show, Swift took to Twitter to thank the longtime rockers for the opportunity. "Filing this under 'never in my wildest dreams.' Thank you @RollingStones for inviting me to Chicago to sing with you."
Swift is the latest guest to join the Rolling Stones onstage during their current "50 & Counting" tour -- with performers in other cities including Dave Grohl, Tom Waits and Katy Perry.