'You're So Vain': Taylor Swift duets with Carly Simon [VIDEO]

Taylor Swift's duets with her musical predecessors haven't always been well-received -- she was famously off-key during her performance of "Rhiannon" at the Grammys with Stevie Nicks a few years ago.

But the 23-year-old starlet tried again on Saturday night, inviting legendary singer-songwriter Carly Simon to join her onstage for a rendition of "You're So Vain," the 1972 hit about an egotistical mystery man.

"Before I bring out my special guest, I have this question that I've always, always had," Swift told the audience at a tour stop in Foxborough, Mass. "I think a lot of you have probably had this question too, always wondered what the answer is. Who is this song, 'You're So Vain' by Carly Simon, written about?"

"Got to sing 'You're So Vain' with Carly Simon at Gillette Stadium tonight!!!!! Unreal. I could not possibly look up to her more," Swift said after the show.

She hinted at the effort earlier this month, tweeting on July 10: "I feel like I definitely get along with people roughly 45% more if they know all the words to 'You're So Vain' by Carly Simon."

Swift and Simon discussed the duet in an interview with MTV.

"Every girl out there will be thinking of someone when we're singing," Swift said.