The Kardashians star shared behind-the-scenes photos from her photo session for her most recent ad campaign for her new Lemme nutritional supplements on Instagram on September 17.
She is dressed in a bare bra with no straps and matching lingerie that appear to be from the SKIMS line by her sister Kim Kardashian.
And she covers her stomach with her hand in one snap, which prompted many users to express the same thoughts.
Someone commented, "Wait a minute, did I miss that she's pregnant?"
"Nope, but you're lacking a woman's body," Kourtney retorted.
Several more admirers flocked to the Poosh creator to compliment her appearance, including Khloe Kardashian.
Kourtney, a mother of three, has reacted angrily to pregnancy rumours in the past.