Pippa Middleton's derriere has its own Facebook fan sites

Philippa Middleton, the only sister of Kate, Duchess of Cambridge, has earned herself a number of fans on Facebook, with her derriere being the focus of attention.

Philippa or Pippa, as she is called, was noticed as she walked up the aisle at Westminster Abbey during her sister's marriage to Prince William, and the view from the back inspired a number of online fan sites.

There are already three Facebook pages in praise of the 27-year-old maid-of-honour's behind, one of which, the Pippa Middleton Ass Appreciation Society, has nearly 9,000 fans.

By contrast, the Philippa (Pippa) Middleton fan page has around 5,000 followers.

But it is not men as much as women who are buzzing about Pippa's bottom. Particularly the fashion pack, who are as besotted with her enviable figure as they are with her Alexander McQueen dress.

US style blog Fashionista.com published an article entitled In Praise Of Pippa (Especially Her Bum), while fashion blogger Susie Bubble tweeted her observation.

"It has to be said... I'm a tad jels over the pertness of Pip Middleton's arse..." the Daily Mail quoted her as having written.

Fashion editor and author Derek Blasberg also took to Twitter, writing: "Unexpected RoyalWedding facts: Pippa's bum was apparently the centre piece of the nuptials."