"Real Housewives of Beverly Hills" newcomer Lisa Rinna is starting her first season as a housewife with a bang. And this may just prove that Bravo made the right decision in getting her on board. A huge brawl between Rinna and Kim Richards may just be what the show needs to rake in more viewers.

What happened anyway? According to Radar Online's sources, Rinna lunged at Richards at an L.A. nightclub because she didn't like what her co-housewife said. Richards allegedly accused Rinna's husband Harry Hamlin of cheating on his wife.  Obviously, Rinna flipped when she heard it.

"Kim had heard rumors for a while that Lisa Rinna's husband, Harry had been unfaithful. Upon hearing the claim, Lisa went nuts, and immediately lunged at Kim. There are certain things that are just off limits as far as Lisa is concerned, and Harry is on that list," the source said.

The source added, "Lisa attempted to push Kim, and the women had to be physically separated! Lisa even made threats against Kim. It was totally crazy."

Even in the preview for "RHOBH" season 5, it was shown the Rinna tossed a wine glass at Richards.

"Don't you ever go after my f*cking husband," Rinna yelled.

What is Richards' motive for making the accusation anyway? It could be that it's Richards' way of getting even with Rinna. In Amsterdam, the latter became suspicious that the former has started drinking again.  Richards fired back, not anticipating that Rinna would react in such a violent way.

Well, this girl fight is far from over because Rinna is allegedly planning to extract revenge on Richards. An insider said that Rinna is going to expose more lies about Richards when the cast reunites in the reunion show.