Taylor Swift Learns Carly Simon’s ‘You’re So Vain’ Secret: Watch!

The two songwriters hit Gillette Stadium to sing the legendary breakup anthem.

When it comes to breakup songs, Taylor Swift is the master. But of course, there were those bold women who came before her, the honest female songwriters who influenced Taylor — Joni Mitchell, Stevie Nicks, Carly Simon. So when the Red singer got a chance to invite Simon onstage in Foxborough, Massachusetts, Swift jumped right on it.

The two sang Simon’s breakup anthem “You’re So Vain” at the Gillette Stadium as if it had been Taylor’s hit all along. “Vain” has the same attitude of many of Swift’s songs, stabbing the heartbreaking boyfriend right back without revealing his identity.

“When I heard ‘You’re So Vain,’ I thought, ‘That is the best song that has ever been written,’ ” Swift said in behind-the-scenes footage from the Red Tour. “That is the most direct way anyone has ever addressed a breakup. It’s amazing.”

Backstage, the singers had a sisterly connection, holding hands and bonding over their mutual love for songwriting.

“It’s a song that really that really developed that style of mine,” Simon said, beaming. “A lot of it was not knowing that I was developing that style.”

” ‘Cause a lot of things happen by accident, don’t you feel?” Carly continued, turning to Taylor, who was giddy with excitement.

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“Yeah,” Taylor answered, looking her directly in the eye, “especially with songwriting.”

The women belted the song for the sold-out crowd, directing a sea of handclaps and karaoke sing-alongs.

“It was just so wonderful that I just want to do it again,” Carly said after the performance. “She was so great. She really led me through my own song. She was just loving of the whole thing. And we loved each other and we moved together and apart. It was dramatic.”

Simon has only revealed the subject of the song to a few people — Is it about ex-husband James Taylor? Mick Jagger? Ex-boss David Geffen? But she did tell Swift. And while Taylor is loyal to her Swifties, she couldn’t get her new friend to divulge the secret to her new fans.

“I was thinking she might tell you, but I do know now,” Taylor said coyly, lifting a finger to her lips.

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