It was possibly one of the early seventies' biggest mysteries. Just who was the unnamed playboy Carly Simon sang about in "You're So Vain"? True, there were plenty of suspects lurking in the shadows. But it would seem that the answer isn't Mick Jagger, Jack Nicholson, David Cassidy or even Warren Beatty -- as was first thought, although he was implied in her memoirs. The clue appeared when she sang an unknown (and previously unheard) fourth verse. And the playboy's name may not be quite so well known after all.

Cloak and dagger mystery

So the cloak and dagger mystery has finally been revealed. The playboy in question is apparently Willie Donaldson.

A man who had the distinction of being the first to break her heart following a somewhat whirlwind romance. But who, exactly, was he? To start with, his was a life of extremes. He had a privileged upbringing and he didn't lack talent, having been a producer and comedy writer who was largely responsible for the emergence of Sylvia Plath and for being the first to bring Bob Dylan to Britain. But it's fair to say he gave in to extremes of the other sort, and, despite his involvement with Carly Simon, among others, wasted his potential and ended up bankrupt -- passing away in a dingy Chelsea flat.

Speculation about who the mystery man's identity was heightened at the time, because Carly had only married James Taylor shortly before the song's release. A Los Angeles radio station even held a phone-in ballot.

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But it does say a lot about Carly Simon's resilience, however, when you consider the secret has been under lock and key for 45 years, without even so much as a hint. Though, ironically, she did say at the time that she never would reveal his identity, maintaining that it would be no advantage to anyone.

'Boys in the Trees'

Now aged 71 and living in Martha's Vineyard, Carly Simon's memoir "Boys in the Trees" lays her insecurities and emotions on the line for all to see. Largely written about her marriage to James Taylor, it contains one of the more poignant moments, when she reveals that she took up singing to help cure her stammer. She's crossed paths with several famous people during her life -- Albert Einstein and Jimi Hendrix among them -- and even shared a transatlantic encounter with Sean Connery. Still, the one intriguing secret behind "You're so Vain" has remained just that -- despite a section in the book being devoted purely to the song.

Even though the truth has finally been revealed, she makes no secret of how deep her relationship with Warren Beatty was, despite his notorious reputation as a womanizer. She fell so heavily for him that you begin to understand why the theories behind the song became evident. Fortunately, the lady herself was in no hurry to reveal them.