9021-go. The drama has ignited in Beverly Hills, with Kim Richards saying she's "disgusted" with costar Lisa Vanderpump after the Real Housewives of Beverly Hills stateswoman raised allegations of infidelity on the part of Kim's brother-in-law, Mauricio Umansky, during the premiere episode on Monday.

As Breaking Celebrity News reported, British-born Vanderpump put her one-time pal Kyle Richards on the spot, casually dropping into conversation stories about her realtor husband’s alleged cheating – all in front of their daughter Portia!

The drama didn’t sit well with Kyle’s sister, who took to her Bravo blog to slam the Vanderpump Rules star.

“When I saw and heard what Lisa said about Kyle and Maurice in front on my niece Portia, I was disgusted, but not surprised!” she wrote.

“This is behavior I have seen for years!! But she is showing her colors more and more!

“If I were Kyle, I personally wouldn't have her in my home again!”

For her part, Lisa tried to defend her actions, explaining in her own Bravo blog that she wanted to address the rumors head on.

“I would prefer face-to-face to acknowledge them and then in the same breath ridicule the constant nonsense,” Lisa wrote.

Lisa insisted that she didn’t believe the cheating rumors and had even tried to leap to her costar’s defense a few days prior to the showdown.

“I had been at an event a couple of days prior and publicly denounced the validity of these rumors regarding Mauricio on the red carpet,” she wrote.