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The singer has confirmed who she wrote the second verse of the song about but the first and third verses are still a mystery!
Beatty dated Simon for a short while in the early 70s. He more than rose to the song's lyrics when he thanked her for writing the song about him. He stated in a 2007 interview: "Let's be honest, the song is about me." But he's wrong, well partly. Carly admitted in an interview with People magazine that the second verse is about him but she won't admit who the other two verses are about. But we've got some ideas...
Jagger contributed uncredited backing vocals to the 1972 track. Although Simon claimed in 1983 that the song was not about Mick Jagger, a certain Angela Bowie resparked the rumours in 1993 when she claimed to be the "wife of a close friend" of the man mentioned in the song.
Simon married Taylor on 3rd November 1972, the same month that You're So Vain was released. She has said that the song is "definitely not" about him.
In the 2010 version of You're So Vain, the name 'David' is whispered backwards about two and a half minutes into the track. Suspicions immediately turned to David Bowie, a name bandied about at the time, who could have easily "walked into the party, like you were walking onto a yacht."
Simon has said in interview that the man's name features the letters A, E and R. Teen idol David Cassidy was also a suspect at the time, and his full name is David Bruce Cassidy.
Cat Stevens was preparing for his first American shows at the Troubadour when he met up-and-coming songwriter Simon. They dated on and off for seven months and Cat's haunting ballad Sweet Scarlet is written about her... Was You're So Vain written about him? Many thought so.
Openly gay billionaire record producer Geffen is an unlikely choice, but a name that crops up repeatedly. In May 2014, New York presenter Howard Stern claimed that Simon took him aside and whispered three names in his ear. He thought one of the names might have been Warren Beaty and the other David Geffen, but he "forgot".
Other suspects included guitarist Dan Armstrong, who Simon wrote her song Dan, 'My Fling' about. However, the greatest certainty may be that we will never know for sure. Simon recently told People magazine that she won't reveal the answers until "at least they know it's about them".