SIMON’S WILD 50th B-DAY BASH thumbnail

Idol mogul Simon Cowell blows million on decadent 50th birthday bash.

Snarky Simon went all out to celebrate his big Five Oh prematurely this past Saturday. His birthday actually isn’t until October 7th but when did that stop a party-pal-ooza?

More than 400 pals and gals traveled thousands of miles to Cowell’s bash at billionaire Sir Philip Green’s mansion in Hertfordshire, England.

According to insiders, Simon spared no expense for celeb pals like Sir Elton John and Kevin Spacey dropping a whopping $1.5 million for the party, including $75,000 for a fleet of limos to shuttle woozy guests to and fro.

"I always pick up my own tab whether it’s for four people or 400," Simon said.

Inside the manse, ginormous images of Cowell were plastered everywhere .  Even the waiters wore masks bearing his grinning visage.

Pre-recorded birthday wishes from David and Victoria Beckham and Jen Aniston blared from  giant screens as supermodel Kate Moss serenaded him with "Happy Birthday"

Some of the A-Listers included American Idol co-stars Ryan Seacrest and Randy Jackson, Naomi Campbell, Sharon Osbourne, Gordon Ramsay, Olivia Newton-John, Danii Minogie AND his 82-year-old mom Julie.

Paula Abdul, who ankled the hit show, did not in attend the self indulgent festivities.