Princess Beatrice and Princess Eugenie attended Sir Elton John's prestigious ball with their mother Sarah Ferguson, the Duchess of York.

Princess Beatrice wore a nude Elie Saab net and flower gown

Source: http://www.redcarpet-fashionawards.com/2011/06/24/princess-beatrice-in-elie-saab-couture-13th-annual-white-tie-and-tiara-ball-to-benefit-elton-john-aids-foundation/

Vivienne Westwood's dress worn by Princess Eugenie

Read more: http://www.dailymail.co.uk/tvshowbiz/article-2007504/Well-suits--Princess-Eugenie-recreates-Ascot-success-red-gown-Elton-Johns-White-Tie-Tiara-Ball.html

Alexander McQueen's dress worn by Princess Eugenie at Royal Ascot 2011

                                                                Alexander McQueen

                                                             Cowl-neck wool-crepe dress

http://www.net-a-porter.com/product/164045?resType=single&keywords=164045

Princess Eugenie of York (C) talks to friends during day five of Royal Ascot at Ascot Racecourse on June 18, 2011 in Ascot, United Kingdom.

Princess Anne and Princess Beatrice Royal Ascot race meeting, Ladies Day, Berkshire, Britain - 16 Jun 2011

Princess Eugenie looks at horses in the Parade ring on day three of Royal Ascot at Ascot Racecourse on June 17, 2011 in Ascot, United Kingdom.

Princess Beatrice and Princess Eugenie (R) arrive for the opening day of Royal Ascot at Ascot Racecourse on June 14, 2011 in Ascot, United Kingdom.

Princess Eugenie (L) and Princess Beatrice share a joke as they attend the annual Order of the Garter Service at St George's Chapel, Windsor Castle on June 13, 2011 in Windsor, England.

Princess Eugenie of York, George, Earl of St. Andrews and Katharine, Duchess of Kent stand on the balcony of Buckingham Palace after the Trooping the Colour Parade on June 11, 2011 in London, England.

Britain's Princess Eugenie (L) and Princess Beatrice arrive at Epsom Racecourse in southern England June 4, 2011.

25th December, 2010: Christmas Day and members of the royal family on their way to the church service at Sandringham. Here, Princess Beatrice.

Princess Eugenie leaves Morton's Club London, England - 26.11.10

Princess Eugenie leaving Whisky Mist nightclub, London, England - 08.09.10

Princess Beatrice and Princess Eugenie at Alice Ferguson wedding to Nick Stileman at All Saints Church, Dummer, Hampshire

28th August, 2010