Back in 2011 the world seemed to be fascinated with Pippa Middleton's butt. The 31-year-old's derrière was splashed across the front pages of magazine tabloids after she rocked a white, form-fitting Alexander McQueen dress at her sister Kate Middleton's wedding to Prince William.

Well, that was a few years ago and the world has moved on. For the last month, Kim Kardashian's bottom has been the talk of the town. In an essay for The Spectator's Christmas Special, Middleton discussed Kardashian's attempts to "break the internet" and the American obsession with big butts.

"No year is complete without a bottom story, and the 'Rear of 2014' award undoubtedly goes to Kim Kardashian, after her posterior exploded all over the internet last month," Middleton wrote. "I must say that mine -- though it has enjoyed fleeting fame -- is not comparable."

"But the Kim butt story did make me pause. What is it with this American booty culture? It seems to be a form of obsession," she continued. "Kim's aim, apparently, was to break the internet, but I'm not sure she's going the right way about it."

Kardashian probably won't respond to Middleton's slight jab, but the "Keeping Up With the Kardashians" star did defend the photos, telling Australia TV show "The Project" last month that she wanted to pose nude to flaunt her post-baby body.

"[I have] an even better body after having the baby than I did before," Kardashian said. "I'm very confident about [my body]. It was just a little token before I have to go through [pregnancy] again."

"As a role model I'm not saying anyone else should do that, but for me it was an art project and it taught me to do what you want to do," Kardashian added. "I'm never one to preach, but I felt really positive and really good about myself. I love the photos. I did it for me. I hope other people like them."