As Catherine enjoys her honeymoon with new husband Prince William after a flawless royal wedding, back home her little sister Pippa has sparked a media storm all of her own.
The two sisters had long been seen together at parties, the pair strangely interchangeable with their glossy brown hair and figure-hugging dresses.
But at the royal wedding on April 29, it was Pippa who emerged the star for many of the two billion viewers worldwide, looking gorgeous as maid of honour in a figure-hugging white Alexander McQueen dress.
Twitter exploded into a frenzy of admiration, and more than 200,000 Facebook users have now joined the "Pippa Middleton Ass Appreciation Society".
A mock-up video using footage from the wedding showing close-ups of Pippa's behind has been viewed 550,000 times on YouTube, and a US porn mogul meanwhile has offered her $5 million to star in "one explicit scene".
The 27-year-old fuelled the interest at the wedding by flirting with the best man, William's younger brother Prince Harry, sparking huge online debate about whether a second Middleton sister would soon become a royal bride.
Pippa had been a well-known figure on Britain's social circuit for years, and in 2008 she was named the most eligible singleton in society magazine Tatler. But it was not until a fortnight ago that the world caught up.
Read more: Yahoo news