Guess the celebrity butts playing peek-a-boo during Paris Fashion Week!

These BFFs are currently in Paris for Fashion Week, and besides just showing off their catwalks, they're flashing their derrieres!

Or at least one of them was!

The brunette beauty pictured above was stepping around town in a see-through pants,

which is obviously how she came about to giving the city a full view of her black thong!

Meanwhile, her blonde bestie donned a super tight green mini dress, which nearly rode up to expose her own butt!

So, have you figured out who these leggy girls are?? Well, it's…

Gigi Hadid and Kendall Jenner with Oliver Rousteing, duh!!

But Kendy wasn't just putting some of her rear ASSets on display, because as you can see she also dared to bare her nips in her exclusive Balmain pieces!

Move over, Kim Kardashian West! Your younger sis is upping her street style game!