Taylor Swift Forgot Rolling Stones Lyrics [VIDEO]: Harry Styles' Ex Was Too Star Struck During 'As Tears Go By' Duet with Mick Jagger

Back on June 3, 2013, Taylor Swift joined Mick Jagger and the rest of the Rolling Stones on stage during their "50 and Counting" tour for a duet performance of "As Tears Go By." In recent interviews, the 23-year-old songstress revealed that singing with Jagger at the Stones' Chicago concert was one of the best moments of her life and that she was extremely star struck by Jagger and his band. The "I Knew You Were Trouble" singer also revealed that both she and Jagger forgot some of the lyrics to "As Tears Go By" and simply laughed it off in front of the crowd. They even turned it into a short dance number, too!

"We were just kinda goofing around and we started dancing, like waltz-like over-exaggerated ballet moves. And then we started twirling around the room," Taylor told Country Weekly. "And it was hilarious, because we forgot the words and we just started laughing. We ended up incorporating a twirl into the performance, I think, in homage to the hilarious musical rehearsal that we had that day."

Taylor was referring to her time spent backstage and during the pre-show rehearsal with Jagger when the two were dancing around for fun.

Swift said she was in awe of the rockers and had plenty of compliments for Mick, Keith, Ronnie and Charlie. Taylor explained why she admires the Rolling Stones, saying, "Mostly because of their attitude. Because of their hospitality. Because they hand-write notes, thanking you for being there. Because you get to get pictures with them and hang out with them."

Check out a video of Swift and Jagger apparently forgetting the lyrics to "As Tears Go By" right here: