It's been three years since the royal wedding, but royal watchers are still talking about Pippa Middleton's derriere.

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Kate Middleton's sister has been accused of enhancing her backside, which became famous when she followed her sister into her wedding to Prince William in April 2011 in a stunning well-fitted white Alexander McQueen dress.

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Stephane Bern, A Knight of the Order of Grimaldo in Monaco and an etiquette expert, argues that Pippa, 30, wore a "false bottom" for the big day.

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"Of course she had a false bottom,” Bern said on his talk show on channel France 2. "I repeat it: she had a false bottom. You take her away from that and she has normal buttocks."

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Bern added: "It was an optical illusion; she knew there were a billion people watching. It was the moment to show it."

The younger sister to the Duchess of Cambridge isn't unfamiliar with such accusations.

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Middleton joked about the world's fascination with her backside during her first-ever public speech on Feb. 25, 2014, at an event in London, laughing: "As I have found out, recognition has its upside, its downside and—you may say—its backside."

This article originally appeared on Usmagazine.com: Pippa Middleton Accused of Wearing "False Bottom" at Royal Wedding