Simon Cowell’s letter: a warning to his party guests

Pop music's most powerful man Simon Cowell is 50 next Wednesday, and his birthday bash tomorrow night is set to be the party of the year - if the breathless press reports prove accurate.

But far more interesting than details of his lavish soiree is the window into Cowell's psyche afforded by an extraordinary letter he has written for the Daily Mail.

Addressed to his early-1990s self, the 3,500 words are a rejoinder to his critics who accuse him of being self-obsessed and a purveyor of "all that is shit" - as a former boss describes him. Most important, it tells us what an "idiot" he was then and how much he has changed after learning from his mistakes.

The letter offers us an all-too-brief sketch of a young Cowell ruined, tired and sick with worry following the collapse of his record label. It describes his part in the excesses of the 1980s and the money he splashed out on music mogul clichés - open-top Porsches and bottle after bottle of champagne at trendy nightclubs.

"You and your friends get absolutely hammered and who always picks up the bill? You do," he writes. "Every night you say: 'This is on me.' Why do you do that? Well, I like to think it is because underneath it all, you are a generous guy. You are, but to be honest, you are also a bit of a flash git."

Of course, all that has changed - or has it? Cowell, apparently, is picking up the bill for his £500,000 birthday party himself. Helping him spend all that money is Lady Green, the wife of Cowell's business partner Sir Philip Green, who has organised the venue (Wrotham Park, near Barnet), the transport (limos and charter planes) and the flowers (no lilies - Simon doesn't like the smell).

The guests are exclusively A-list - Donald Trump, Elton John, Kylie Minogue - even if the entertainment is distinctly ordinary: Leona Lewis and Kate Moss singing a Lily Allen number.

Hopefully the event won't remind Cowell too much of the hedge fund charity ball he had to walk out of recently because it made him feel ill. "My God, this reminds me of what it used to feel like in the Eighties. It is all hot air, it's fake," he writes in his letter to himself.

Maybe he's just referring to one of his "black moods". "Sometimes, when friends are over," he reveals, "you want to ask them to leave." Which does not bode well for the 400 guests setting out for Wrotham Park. ·