• Real Housewives of Orange County alum Heather Dubrow just posted a vid of herself dancing in a black bikini.
  • The clip was in response to RHOBH star Lisa Rinna's earlier bikini pic.
  • "This is Fifty baby !!!" Heather captioned the vid.

It's a (friendly!) battle of the hardbody Housewives: Last week, Real Housewives of Beverly Hills star and actress Lisa Rinna posted a jaw-dropping Instagram of herself in a leopard-print bikini with the caption "55 and Shameless." Now, her one-time Orange County counterpart Heather Dubrow is showing a little skin of her own on social media.

In an Instagram post on Monday, Heather did a little happy dance wearing nothing more than a little black bikini. (Those abs-seriously!)

"This is Fifty baby !!!" she wrote. "Trying to keep up with @lisarinna !!! #bodygoals "

View this post on Instagram This is Fifty baby !!! Suit by @seafollyaustralia sandals by @pedrogarciashoes tan by @milliondollartan body by @boxhausoc @otfcdm !!! Trying to keep up with @lisarinna !!! #bodygoals A post shared by Heather Dubrow (@heatherdubrow) on Apr 6, 2019 at 6:07pm PDT

All I have to say is: Mission accomplished, Heather!

Now, if you're curious how Heather keeps her body tight, she kindly left a few clues in the caption, tagging studios Box Haus and Orangetheory Fitness . She also attributes her overall health and wellness to The Dubrow Diet-a system of interval eating (aka intermittent fasting) that she co-created with her plastic surgeon husband Terry Dubrow, MD. The system is explained in detail in their best-selling book of the same name, which was published last year.

"Terry just turned 60; I'm going to be 50 in January. People see pictures of us and ask, 'How do you have these ageless bodies?' And this is how; it's the way we eat; it's the way we exercise, and we put it all down in The Dubrow Diet," she told Bravo in late 2018.

So who will be the next housewife to post a seriously slammin' selfie? My money is on Ramona Singer...