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Kate Middleton
Kate Middleton featured on the top spot of Vanity Fair's best-dressed celebrities for 2010, 2011 and 2012.Reuters
Kate Middleton
Kate Middleton in an Alexander McQueen gown during her trip abroad in 2011.Reuters
Princess Letizia
Spanish Crown Prince Felipe (R) and his wife Princess Letizia arrive at a gala dinner organised on the eve of the abdication of Queen Beatrix of the Netherlands and the inauguration of her successor King Willem-Alexander at the Rijksmuseum in Amsterdam April 29, 2013.Reuters
Princess Letizia
Spanish Crown Prince Felipe and Princess Letizia arrive to attend a religious ceremony at the Nieuwe Kerk church in Amsterdam April 30, 2013.Reuters
Princess Madeleine
Princess Madeleine, 30, daughter of Sweden's King Carl XVI Gustaf and Queen Silvia, married US-British banker Christopher O'Neill, at the royal church in the royal castle in Stockholm on 8 June, 2013.Reuters
Princess Madeleine
Princess Madeleine of Sweden arrives at the Place du Palais to attend the religious wedding ceremony for Monaco's Prince Albert II and Princess Charlene at the Palace in Monaco July 2, 2011.Reuters
Princess Madeleine
Sweden's Princess Madeleine, King Carl XVI Gustaf and Queen Silvia arrive at the American-Scandinavian Foundation gala in New York October 21, 2011.Reuters

Royalty is well represented in Vanity Fair's Best Dressed List for 2013, with Kate Middleton, the Duchess of Cambridge, joined by Princess Letizia of the Asturias and Princess Madeleine of Sweden.

The duchess' pregnancy bump did little to stop her from appearing on the list for the fourth straight year but the 31-year-old royal did concede top spot, after two consecutive years. American actress Kerry Washington, who shot to fame with Quentin Tarantino's Django Unchained earlier this year, is Vanity Fair's new No 1.

Kate remains as one of the leaders on the list though, with only singer/actor Justin Timberlake between her and top spot; the duchess was third.

Crown Princess Letizia (she is married to Felipe, the Prince of Asturias and heir apparent to the Spanish throne) has often been compared to Kate for similarities in fashion picks and the fact the royals share a commoner-to-princess story.

However, this is her debut appearance in the best-dressed list. Vanity Fair praised her for the blue lace Felipe Varela gown she wore at the crowning ceremony of King Willem-Alexander of the Netherlands in April, calling it a "notable ensemble". The princess wore matching heels by Margriet and a Maria Nieto hat for the event.

Princess Madeleine's appearance on the list was due to an elegant bespoke ivory silk, organdy and Chantilly lace wedding gown by Valentino Garavani.

Check out the slideshow to view some of the best-dressed moments of Princess Letizia, Princess Madeleine and the Duchess of Cambridge...

READ: Kate Middleton on Vanity Fair's List: The Dresses that Won the Duchess Two Best Dressed Awards [PHOTOS]