Bethenny Frankel, 51, displays her impressively taut abs as she flashes Skinnygirl underwear

Bethenny Frankel put her impressively taut abs on full display on Thursday as she gave her Instagram viewers a peek at her underwear, which was made by her brand Skinnygirl.

Skinnygirl by Bethenny Frankel, Seamless Shaping Briefs Underwear Black/Taupe/Nude - 3 Pack (Large) at Women's Clothing store

Bethenny Frankel flaunts her slender waistline while plugging Skinnygirl bras

Bethenny Frankel Posts Unfiltered Bra-and-Underwear Selfie: 'This Is Me at 50

Bethenny Frankel flaunts her slender waistline while plugging Skinnygirl bras

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Bethenny Frankel Embraces Her 'Real' Body in Unfiltered Underwear Photo: 'This Is Me at 50

Bethenny Frankel, 51, displays her impressively taut abs as she flashes Skinnygirl underwear

Bethenny Frankel, 51, displays her impressively taut abs as she flashes Skinnygirl underwear

Bethenny Frankel Posts Unfiltered Bra-and-Underwear Selfie: 'This Is Me at 50