Taylor Swift joined The Rolling Stones on stage Monday night in Chicago.  Swift and the band performed As Tears Go By.

The song was originally recorded by Marianne Faithfull in 1964.  At the time, Faithfull and Rolling Stones front-man Mick Jagger were dating.  So, it only makes sense that the world's most famous ex-girlfriend sang along on this one.

Swift is one of many stars to join The Rolling Stones on stage during their 50 and Counting tour.  Carrie Underwood, Lady Gaga, Keith Urban, John Fogerty, and Dave Grohl are among the notable performers to join the band on the stage.