They were once the closest of friends, but now Lisa Vanderpump and Brandi Glanville have fallen out and the British matriarch isn’t holding back in her criticism of her newfound nemesis.

During Monday night’s episode of The Real Housewives of Beverly Hills, Glanville, the outspoken mother-of-two shocked her fellow Housewives over lunch when she called costar Carlton Gebbia a “c—.”

"Sorry, unacceptable!” Vanderpump wrote on her official Bravo blog.

"We might be friends, but that stank of her feeling the necessity to be controversial, which is getting a little old.”

Though Eddie Cibrian’s ex-wife claimed she meant the vile comment "as a compliment," many stars weren’t amused.

After the episode, Glanville took to her blog in an effort to defend her brash choice of words.

“I met Carlton's best friend through my girlfriend and she said that Carlton was a girls' girl and 'c---y in a good way,' so I assumed it was safe to repeat this,” she wrote.