Nobody writes a breakup song like Carly Simon and Taylor Swift! The 68-year-old musical legend joined the "We Are Never Ever Getting Back Together" crooner on stage at Boston's Gillete Stadium on Saturday, July 27, to sing a duet of Simon's 1972 classic, "You're So Vain."
"Once we get out there and we have 55,000 in a sing-along, it's just going to be like karaoke night in the stadium," Swift, 23, explained to MTV News in a backstage video. "Every girl out there will be thinking of someone when we're singing."
Swift -- known for her chart-topping hits believed to cover her failed romances with the likes of John Mayer, Taylor Lautner and Jake Gyllenhaal -- followed Simon's lead (and then some!) in singing about her failed relationships. "When I heard 'You're So Vain' I just thought that was the best song that has ever been written," Swift said. "That is the most direct way anyone has ever addressed a break up. It's amazing."
Despite the song's raw emotion, Simon, like Swift, will never admit to the public who "You're So Vain" was written about. "I've already told and I've told you never to tell," Simon told the young singer. "So you know." (The song was long believed to be written about David Geffen or Warren Beatty.)
"I was just thinking maybe she might tell you, but I do know now," Swift teased with a big smile on her face.
Watch Swift and Simon sing "You're So Vain" in the video above and tell Us: Do you like their duet?
This article originally appeared on Usmagazine.com: Taylor Swift Sings "You're So Vain" Duet With Carly Simon