E! NEWS EXCLUSIVE: Take It Off! Kourtney Kardashian Shows Off "Bomb Ass Body" in Naked Photo Shoot—and Kylie Jenner Is So Jealous E! News http://www.eonline.com/shows/kardashians/news/849547/take-it-off-kourtney-kardashian-shows-off-bomb-ass-body-in-naked-photo-shoot-and-kylie-jenner-is-so-jealous Kylie Jenner better watch her back! Kourtney Kardashian is heating up Costa Rica and challenging her sisters' "thrones" in this Keeping Up With the Kardashians sneak peek as she strips down to her birthday suit and poses in a wet and wild photo shoot. Photographer Mike Rosenthal is on hand to capture Kourtney's naked romp in the pool as Kylie, Kim Kardashian and Khloe Kardashian watch their older sis in action. "Kourt, you are giving life right now!" hairstylist Jen Atkin applauds the mom of three as she works it in front of the camera. "You guys are fighting over thrones and I'm just doing what I've always done," Kourtney tells her family. "I'm just sitting on the throne!" "I honestly was worried about you after Penelope," Khloe tells the 38-year-old mama in their confessional. "I did think, like, she's gone. Now, she's YOLO-ing it up, f--king bomb ass body, naked in the pool and your sisters should be afraid of you 'cause you just took the crown." As Kourtney continues to splash around and whip her hair, Mike snaps an amazing picture that makes Kylie green with envy. "What the f--k!" the 19-year-old says after taking a look. "I want to get in. I'm so jealous!" We see you, Kourtney! Watch a brand new episode of Keeping Up With the Kardashians Sunday at 9 p.m., only on E! #bootynaked #poolside #photoshoot #kardashianstyle #kourtneykardashian #kuwtkclips #sundayepisode only on @eentertainment #specialthanks @e_tv_pr checkout @enews