Kim Zolciak recently showed off her growing belly in a little black bikini, posting the photo to Instagram for the world to see, before heading out for a swim.

“Going swimming with the kiddos!” she captioned the pic. “The pool makes me feel so much lighter!”

Lighter is important these days, as Kim is carrying twins. The 35-year old mother of four (outside her belly, at least) found out she was pregnant with her fifth just nine months after her son Kash was born. Kash and 2-year old K.J. are her sons with Atlanta Falcons player Kroy Biermann; she also has two daughters–16-year old Brielle and 12-year old Ariana–from a previous marriage. She says the news that she was carrying twins came as a shock but that she and Kroy are excited.

“I’m having twins and I couldn’t be more excited. I was completely shocked. I had no idea. It was a natural conception, but twins do run in the family, so I guess I shouldn’t have been surprised. I can’t believe I am going to be a mom to six children. It’s going to be very busy, but it’s a dream come true,” she said.