"Good morning," Kardashian, 31, captioned the photo, which placed her gym-toned abs (and everything further south) front-and-center for the camera.
The Strong Looks Better Naked author has been open about her fitness journey in recent months, in which she shed more than 40 lbs.
"I definitely think the physical and the mental go hand in hand," Kardashian told PEOPLE exclusively in January "I feel so good in the gym that it [affects] the rest of my day. It's a healthy addiction. It's like buying your sanity!"
In May, she reflected on all the work she'd done for an interview with Shape.
"I love my shape because I've earned every curve," Kardashian told the magazine. "I work hard in the gym to get it [and] I feel empowered and badass that I was able to accomplish everything I have."