What is Kim Zolciak's secret?! 

The former "Real Housewives of Atlanta" star showed off her fit figure in a new Instagram snap on Tuesday.

Posing from the side with her shirt lifted up, the mother-of-six looks better than ever in her latest selfie!  "I think I see an ab!!!! hey after 6 kids I'll take it!!," the blonde beauty captioned the candid photo. 

We gotta hand it to Kim, she looks amazing just four months after giving birth to twins!

Kim's twins are the 3rd and 4th children for her and hubby Kroy Biermann, who also have sons KJ, 2, and Kash, 1. Kim likewise has two daughters, Brielle, 16, and Ariana, 12, from a previous relationship.

Whatever Zolciak's secret it, it's definitely working -- how do you think the reality star looks?

Tell toofab in the comment section below and click "Launch Gallery" above to see even more celebrity post-baby bods!  

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