Kim Zolciak, expecting twins with husband Kroy Biermann, showed her bare pregnant belly in a bikini picture on Instagram on Sept. 14 Credit: Courtesy of Kim Zolciak

Tres saucy! Kim Zolciak -- who is expecting twins with husband Kroy Biermann -- dared to bare her pregnant belly in an itsy bitsy teenie weenie black bikini on Saturday, Sept. 14.

The Real Housewives of Atlanta star, 35, took to Instagram to share the sexy selfie, in which she rocks a French maid-inspired two piece (black with white eyelet lace trim). "Going swimming with the kiddos!" she captioned the picture. "The pool makes me feel so much lighter!"

Zolciak has not been shy about showing off her fifth pregnancy. She first confirmed the news on the June 25 episode of her Bravo spinoff series Don't Be Tardy.

"Pregnant, pregnant, pregnant, pregnant, pregnant, pregnant," she said on the show, reading the results from several at-home pregnancy tests to her footballer husband, 28. "Kroy, we have not one negative test."

"How exciting is that, love muffin?" she exclaimed as she hugged the Atlanta Falcons player. "You did it again, lovey...Are you excited, love muffin? It must be the athlete sperm."

A couple of months later, in August, sources confirmed to Us Weekly that the mom of four was expecting twins. (Zolciak has two daughters, Brielle, 16, and Ariana, 12, from a previous relationship, as well as two sons, KJ, 2, and Kash, 13 months, with Biermann.)

"I still can't believe that God blessed me w/ 2 more bundles of joy!" she tweeted on Sept. 7. "It's truly amazing to see the babies on ultrasound! Seeing 2 is insane!"