Simon Cowell's girlfriend Terri Seymour, right, arrives with a friend
Other guests, including Princess Beatrice and her mother Sarah Ferguson, Dame Shirley Bassey and Tom Jones, were greeted by Elvis Presley lookalikes.
The Duchess of York wore her low-cut white dress with a Marquise diamond choker with matching earrings. Princess Beatrice also wore jewellery by Chopard, the jewellery company which helped to organise the party.
As guests arrived they made their way past the original stage inflatables from Elton John's Red Piano Las Vegas Show.
They were then led down a hot-pink carpet, and past ice sculptures carved into the shape of famous Las Vegas hotels and draped with diamond jewellery.
One offer at the fund-raising auction was a day of tennis coaching by Roger Federer, as well as the latest Audi A8 and the most exclusive convertible Rolls Royce Drophead Coupé. All proceeds from the evening will go towards the Elton John AIDS Foundation.
After the auction, the entertainment was provided by Dame Shirley Bassey, Tom Jones and the party host himself.
Last year, the White Tie And Tiara ball cost £1,000 a head and raised £4.6 million for charity.
The Dailymail