Simon Cowell, has been told to ‘expect the unexpected’ at his surprise birthday bash this weekend, which will be attended by 17 of his ex-girlfriends, according to the Daily Mirror.

Ex and close pal, model Jackie St Claire, who made the comments, will be hosting the lavish white-themed party in West London.

Exes in attendance will include Terri Seymour and Sinitta and possibly even Jasmine Lennard, his one-time fling.

The X Factor judge, who turns 50 in October, will be celebrating his milestone birthday three months early due to his busy filming schedule, which is set to become a lot more hectic with the launch of the new series of the ITV1 talent show.

Britain’s Got Talent finalists Stavros Flatley will be performing and guests will include Simon’s pals Cheryl Cole, Dannii Minogue, Louis Walsh and Piers Morgan, as well as American Idol judges Paula Abdul and Randy Jackson.

A friend said: “It is certainly going to be an extra special night for Simon. He has no idea it’s a party for him.

“Jackie told him it was her birthday to make sure he was on time for once.”