Rachel Zoe is known for moving at a rapid pace, but during the eighth month of her pregnancy, the 40-year-old fashionista finally realized she needed to slow down.

In a sneak peek from Tuesday's all-new episode of The Rachel Zoe Project, the stylist-turned-designer invites her husband Rodger Berman to join her for a private prenatal yoga session.

"I'll make you look bad, even pregnant," she teases him. "And I have a Stella McCartney yoga mat."

Once the session is over, the instructor tells Berman that his wife -- who has often been criticized for her slender frame -- is "impressively strong for not getting to work out on a regular basis."

The Rachel Zoe Project airs Tuesday at 10 p.m. EST on Bravo.