Khloe Kardashian Dubs Kourtney a 'MILF' in Ab-Tastic Gym Selfie

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and Khloe Kardashian are proving that hard work definitely pays off in their latest midriff-baring selfie.

The sisters shared an ab-solutely fierce Instagram snap on Saturday, revealing their toned tummies while donning similar all-black workout gear.

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“Gym selfie with the MILF,” Khloe captioned the mirror selfie. Kourtney later reposted the same pic writing, “Double gym selfie.”

Khloe recently opened up about her weight loss journey, admitting that it was not an overnight transformation.

"For me, it's about lifestyle changes," the 31-year-old reality star revealed on Live! with Kelly and Michael last week. "I dieted forever -- I'm a yo-yo dieter, yo-yo weight gainer -- and I was like, 'Ok, I need to make a change.'"

"It's not about losing 30 pounds in 30 days -- that's unrealistic," she continued. "So, I started making lifestyle changes and working out often. I started slow. It's been about three years, and I've kept the weight off."

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It's no secret that her 36-year-old sister has been hitting the gym hard since splitting from longtime boyfriend Scott Disick in July. The mother of three has continued to stun us with her fit figure, which she's happily flaunted with Instagram selfies and while going out with friends, including Justin Bieber, in Los Angeles.

Kourtney isn’t the only star who's wowed with their revenge bod following a heartbreaking split -- find out who's made the list recently in the video below.

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