A Rolls-Royce state car at the Royal Mews on March 21, 2011 in London, England. The car will transport Prince Charles, Prince of Wales and Camilla, Duchess of Cornwall on the day of the wedding of Prince William and Kate Middleton. (Photo by Dominic Lipinski - WPA Pool/Getty Images)

RAF volunteers from stations across the UK, who will be acting as the lining party during the Royal Wedding, practice drills in the Parade square at RAF Holton on April 26, 2011 in Aylesbury, England. The members will make up the Queen's Colour Squadron, and will be lining the route between Buckingham Palace and Westminster Abbey during the wedding of Prince William and Catherine Middleton on April 29, 2011. (Photo by Dan Kitwood/Getty Images)

A general view of a royal wedding themed window display at Agent Provocateur in Pont Street, Chelsea on April 29, 2011 in London, England. The marriage of the second in line to the British throne is to be led by the Archbishop of Canterbury and will be attended by 1900 guests, including foreign Royal family members and heads of state. Thousands of well-wishers from around the world have also flocked to London to witness the spectacle and pageantry of the Royal Wedding. (Photo by Adrian Murrell/Getty Images)

Boys in ceremonial uniform at the civil wedding ceremony of American actress Grace Kelly and Rainier III, Prince of Monaco at the Prince's Palace of Monaco, 18th April 1956. Original publication: Picture Post - 8336 - The Hour Of Marriage - pub. 28th April 1956.

Vladislav Doronin and Naomi Campbell attend the religious ceremony of the Royal Wedding of Prince Albert II of Monaco to Princess Charlene of Monaco in the main courtyard at the Prince's Palace on July 2, 2011 in Monaco. The Roman-Catholic ceremony follows the civil wedding which was held in the Throne Room of the Prince's Palace of Monaco on July 1. With her marriage to the head of state of the Principality of Monaco, Charlene Wittstock has become Princess consort of Monaco and gains the title, Princess Charlene of Monaco. Celebrations including concerts and firework displays are being held across several days, attended by a guest list of global celebrities and heads of state. (Photo by Sean Gallup/Getty Images)

Girls pose during a photocall to promote the Big Royal Wedding Sleepover at “Camp Royale” on Clapham Common on March 8, 2011 in London, England. The “Pop Up” campsite will cater for up to 10,500 people between April 28 and May 1 to coincide with the weekend of the Royal Wedding on April 29. (Photo by Dan Kitwood/Getty Images). LONDON, ENGLAND – MARCH 08 2011

In this image provided by the Ministry of Defence, Prince William takes the controls of a Sea King helicopter on April 14, 2011 in Holyhead, Wales. Search and rescue co-pilot Prince William, based at RAF Valley will marry his fiancee Catherine Middleton in Westminster Abbey in London on April 29, 2011. (Photo by MoD Crown Copyright via Getty Images)

General view of the screens in Hyde Park to showing the Royal Wedding on April 29, 2011 in London, England. The marriage of Prince William, the second in line to the British throne, to Catherine Middleton is being held in London today. The Archbishop of Canterbury conducted the service which was attended by 1900 guests, including foreign Royal family members and heads of state. Thousands of well-wishers from around the world have also flocked to London to witness the spectacle and pageantry of the Royal Wedding and street parties are being held throughout the UK. (Photo by Tom Dulat/Getty Images)