Kim Zolciak Kim Zolciak

Kim Zolciak showed off her growing baby bump, sending out a picture on Instagram of herself in a bikini.

"Going swimming with the kiddos! The pool makes me feel so much lighter," Zolciak wrote on Saturday. The former Real Housewives of Atlanta star and her husband Kroy Biermann are expecting twins this winter.

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The babies will be the fifth and sixth children for Zolciak. Zolciak, 35, and Biermann, 28, have two sons together — Kroy Jr., 2, and Kash, 1. Zolciak also has two daughters — Brielle, 16, and Ariana, 12 — from previous relationships. Zolciak and Biermann, a defensive end for the Atlanta Falcons, married in 2011.