Kate Middleton stepped out for the Diamond Jubilee River Pageant today in London -- wearing a version of a dress Kim Kardashian wore in 2011!
The Duchess was spotted in a red Alexander McQueen dress alongside Prince William for the boat parade, pairing her look with a matching fascinator and clutch, nude pumps and a brooch.
"Keeping Up with the Kardashians" star Kim K. wore a similar version of the McQueen dress back in August 2011 -- days before her wedding to Kris Humphries.
Kim's version of the dress was sleeveless and she paired it with a silver clutch, a bold necklace and snake print Louboutins.
Who do you think pulled the look off better? We're giving this one to Kate for keeping it classy and elegant ... and having a Prince by your side certainly doesn't hurt!
Vote for who you think wore it better in the gallery above!