When you're around the Kardashian clan, you never know when someone is taking a selfie!
Khloe Kardashian learned this the hard way when her younger sister, Kylie Jenner, snapped a picture with pro makeup artist Joyce Bonelli, which actually captures her topless in the background.
Bonelli called attention to Khloe's racy accidental photobomb on Instagram on Thursday, writing, "@kyliejenner it's really not about us though @khloekardashian."
PHOTOS: Kim Kardashian's Sexiest, Most Scantily Clad Selfies
We doubt the 30-year-old reality star was too upset though, especially since she's been taking to her own Instagram to show off her amazing body. Earlier this week, she flaunted her slim stomach and her famous derriere in a stylish all-grey outfit.
"About two years ago I decided to turn to fitness as a form of therapy and as a stress reliever," she explained in February, when she Instagrammed before and after pictures highlighting her serious slim-down. "People love to call me the fat one but as weird as it sounds, I still don't think I would consider myself fat back then. Definitely overweight and unhealthy, yes ... I started slow and eventually I started working out 4 to 5 days a week. We all have to start somewhere and doing something is better than nothing at all."
VIDEO: Khloe Kardashian Lasers Cellulite Off Her Booty as Kylie Jenner Finally Admits the Truth About Her Lips
ET recently caught up with Khloe's trainer, Gunnar Peterson, who gave us a few tips on how to get results like Khloe's! Watch below: