She captioned the photo: 'My girl craved some vitamin D #5months.'
Refaeli wore a teeny stripped navy and white bikini while showing off her growing belly.
It's not the first time she has dropped big news on the social media platform. Back in January, Refaeli announced that she and hubby Adi Ezra were expecting their first child with a photo of a positive pregnancy test.
The former Victoria's Secret model is due this August, and we bet her little tyke will be just as stunning as her mom.
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Pregnant Bar Refaeli drops big news in bikini selfie
A tribute to YEMANJÁ 🌊🌊🌊🌊🌊
@victoriassecret swim special coming so soon - March 9 th on cbs 👙👙👙👙 #stbarth @ed_razek
Good morning!!! 📸 @davidbellemere @victoriassecret @thelionsny
Latest obsession @elisabethbelljewelry gold sea star earrings!! #Love ⭐️🌟💫
That pineapple life 🍍🍍 @victoriassecret #vsswim2015
Also don't forget to watch the #vsswimspecial March 9th on @cbstv 👙👙
Oh summer. Pls hurry. 🙏🏻🌞🌴🌍🌙⭐️🌊
happy birthday @taylor_hill !! My life wouldn't be the same without your sarcasm, jokes, and words of encouragement. Really couldn't ask for a better friend!! Thanks for always believing me and I still love you even though you beat me at jetbooting!!!! 😂😜🎉🎈
Miami nights 💥
Congrats @josephineskriver for becoming VS newest angel 💋💕💋💕💋💕
@adrianalima 👼🏼💘 #vsfashionshow
#Repost @insta_bobb #stbarths makes me happy! #endingwithabang @nomadrj @tinat2 @fulviafarolfi @diegodasilva_ @victoriassecret @jeromeduran