But no one was prepared for the fashion frenzy her sister and maid of honor, Pippa, created.
"There was really no anticipation about Pippa's dress," said Dan Rentillo, design director for David's Bridal told the New York Times. "I can't think of one where there was such a fuss over the bridesmaid's dress."
Pippa may have single-handedly ended the era of ugly bridal party attire with her curve-hugging silk gown by Sarah Burton of Alexander McQueen. She also sparked a mad dash to duplicate her look just in time for the upcoming wedding season.
Fashion label Faviana, which is producing versions of both Kate's and Pippa's reception and ceremony dresses, is hoping to have the knockoffs in stores as early as late June, Omid Moradi, the company's chief executive told the Times.
The maid of honor frock is currently available for pre-order on eDressMe.com for $298, while Kate's lace long-sleeved gown can be yours for the low price of $498.
But which dress will more brides buy? "The Kate, the Kate for sure," Mr. Moradi predicts. "She's the princess!"