The revealing snapshot, posted in the wee hours of Aug. 27, shows Kardashian, 34, lifting up her shirt to expose her flat, toned abs and black bra. "Looks like an angel," Disick, 30, captioned the photo.
Together since 2006, the Keeping Up With the Kardashians stars already have two children together. Son Mason, 3, was born on Dec. 14, 2009, while daughter Penelope, 13 months, was born on July 8, 2012.
Speaking about fatherhood shortly after Penelope's birth last year, Disick said having a family completely changed his perspective. "My son is my world and my daughter is my new world. So, it all combines," the one-time party boy raved to Us Weekly. "It's pretty unbelievable starting another chapter in your life. It's a lot better than not having children."
Added Kardashian: "We're good right now with how things are. We're just trying to figure out our new life with two kids."