What caused Lisa Rinna to ask Dorit Kemsley whether or not people were abusing drugs at her house on Real Housewives of Beverly Hills?

It’s the bombshell that left Real Housewives of Beverly Hills fans totally speechless.

In the final moments of last week’s already-intense episode, Lisa Rinna asked Dorit Kemsley an outrageous question about a party Kemsley had earlier in the season.

“What I want to know is when I was at your dinner, you all got up and left,” the 53-year-old Melrose Place alum asked. “Were people doing coke in your bathroom?”

The query created a room full of jaw-dropped Housewives — especially Kemsley, who quickly denied the accusation in the first minutes of Tuesday’s all-new episode.

“I certainly wasn’t,” she said. “Are you suggesting that I got up from the dinner table and went to do drugs?”

Kemsley then pointed to her 3-year-old son Jagger and 1-year-old daughter Phoenix, telling Rinna, “My house is a coke den? I’ve got two little babies, but they live in a coke den? Are you f—ing kidding me girl? Really?”

Lisa Rinna and Dorit Kemsley
| Credit: Jason LaVeris/FilmMagic; Noel Vasquez/Getty

But Rinna maintained she wasn’t making any accusations — just asking a question. “I was left at that table by myself when everybody got up,” she said. “Why are we all worked up about it? All you have to say is no.”

She then justified her inquiry, reminding Kemsley of the addiction accusations she had made towards Rinna previously.

“You’re talking about me being a Xanax addict somehow,” Rinna said. “If [you’re] questioning me, I have to be open about what I saw. I haven’t said anything about it and I probably wouldn’t have said anything about it until you questioned whether I had a problem with Xanax.”

“What’s so wrong with that?” she continued in her defense. “You intimated that I’m a drug addict. You did. So I can ask the same f—ing question. Just say, ‘I don’t know Lisa and I’ll be done with it.’ You deal with your s— and I’ll deal with mine. Period.”

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By that point, some of the Housewives had come to Kemsley’s defense — including Lisa Vanderpump. “If someone said that to me I would be jumping across the table,” she said. “It’s just getting too mean. It’s getting too mean and too personal. It’s not now about the issue and who said what and who regrets what. I know what you’re doing. Low blow, Rinna. ”

That didn’t stop Rinna. “I don’t care — you know low blow better than anybody, hunny,” she responded.

“Dorit is b—ing. I don’t want to call someone out for something, but I saw what I saw and a behavior speaks pretty loudly,” Rinna confessed to viewers. “I don’t think I have any regrets about what I said. Dorit doesn’t listen. And if people don’t listen, things need to be said to get them to pay attention. I don’t like to have to go there. But I go there with people if they’re not listening or if they’re saying untruths.”

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The two eventually walked away from the argument — though Kemsley’s head was still spinning.

“I can’t for the life of me understand why Rinna would make such a preposterous accusation,” she said. “It’s specifically designed to malign my character. What the hell did I do to merit that? I have two small children. What are you suggesting?”

“It was odd and I didn’t expect it,” she told husband PK Kemsley while back in Beverly Hills. “I thought things were nice with us. I don’t really know where to go with her because she’s someone that kind of freaks me out. She’s like one person one day and another person in another moment. You don’t really know who you’re going to get.”

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PK had an accusation of his own to throw out in response. “There’s a term for that — it’s called schizophrenic,” he said. “I think she’s dangerous.”

While Kemsley debated whether or not she’d be able to forgive Rinna and move forward with her, pals Kyle Richards and Vanderpump were not making any excuses for Rinna’s behavior.

“Rinna gets so upset that you just don’t know what she’s going to pull out of that bag of hers,” Richards said. “But it is going to be one sharp dagger.”

Vanderpump agreed, though she didn’t think Rinna came out the victor this time: “Rinna feels the need to hit back and make Dorit look as bad as possible. She tried that with me and it didn’t work and I don’t think it’s going to work in this case. What else you got Rinna?”

The Real Housewives of Beverly Hills airs Tuesdays (at 9 p.m. ET) on Bravo.