RHOSLC's Mary Cosby Savagely Shades Castmate Heather Gay During Watch What Happens Live Appearance

During her recent appearance on Watch What Happens Live Tuesday, The Real Housewives of Salt Lake City star let her opinions be known as she and fellow guest, Ziwe Fumudoh, played a game of "Versace or Hibachi."

When asked to rate fellow Housewives' outfits, calling them Versace if they were a hit or throwing them on the Hibachi grill if they were a dud, Cosby -- who just last week slammed castmate Heather Gay's necklace choice during Lisa Barlow's Après-Ski party, came for Gay again during the game.

"Mary, did Heather get it right with this Gucci top and chain necklace?" host Andy Cohen asked the reality star.

"No," Cosby, who returned for season 4 after departing the series following season 2, responded. "Do you think it's a fake?" Cohen asked. "I do," Cosby said. "I don't think Gucci makes that. I've never seen a corset in like, a size 14."

Cosby -- who said she actually liked Gay earlier in the same episode -- stood by her controversial comment by noting that it's her "opinion."

Gay addressed Cosby's comments on Instagram, ensuring fans that the designer corset is in fact the real deal. "It's real. And it's spectacular! 😜," the Beauty Lab and Laser owner commented under the @bravobybetches Instagram post of the interaction on Wednesday.

Cosby has come under fire since body-shaming Gay during Tuesday's episode, with fans blasting her on social media.

"Body shaming now too, Mary? Gross. You quite possibly qualify for the worst example of a Christian ever. And that *is* a Gucci corset… excuse me, cors-ket. @heathergay29 can afford to buy her authentic Gucci without swindling her customers in the name of Jesus. #WWHL," someone tweeted.

Another user wrote, "Mary is disgusting & vile. The fact she feels so comfortable fat shaming Heather and talking about the cast's diet is despicable, Team Heather, get Mary off this show."

"not Mary M. Cosby being the worst guest ever. The size 14 comment about Heather was classless," someone commented.

TooFab has reached out to Cosby's camp for comment.