Her tirade might have remained private had she had it without a witness. Instead, details leaked to the media, and the debacle made countless headlines.
Wednesday's episode opened with Dorit Kemsley calling Kyle Richards, who was on location in Georgia filming night shoots for Halloween Ends. Dorit, 46, told Kyle that the group was at Crystal Kung Minkoff's the night before for her birthday party and that Lisa, 59, left early because she was so upset over things Kathy, 63, said about everyone.
In a confessional, Kyle, 53, confirmed she knew some of the things that were said — but not everything. "I don't want to get to a place where I can't repair with her again," she said, holding back tears. "So, it may be best I don't know."
Kathy's outburst was brought up again at an event thrown by Erika Girardi for Pretty Mess Hair. Dorit, Lisa, Crystal, Diana Jenkins, Sheree Zampino, and Sutton Stracke were all in attendance for the event but Garcelle Beauvais, Kathy, and Kyle were not there.
In a confessional, Erika, 51, expressed her thoughts on the matter.
"A lot of articles have surfaced about Kathy's behavior at the nightclub. I do not know how they got this level of detail. This is a juicy story," she said. "Everybody would love to have this story that Kathy Hilton had a meltdown in Aspen at a nightclub, cussing out the managers and screaming in Kyle's face, and acting like an a–hole at the coat check. People saw it."
Charles Sykes/Bravo/Getty; Charles Sykes/Bravo/Getty; Jon Kopaloff/Getty Lisa Rinna, Kathy Hilton and Kyle Richards
Lisa then told Dorit that she was still upset by Kathy's behavior, and Dorit confessed that Kathy had called her, which left Lisa shocked.
"Kathy remembers everything and she's not proud of her behavior at all. This is far more about Kathy and Kyle than it is about anything else. Period. She was very much like, 'My behavior is wrong.' She was apologetic," Dorit shared.
"She tried to silence me," Lisa replied, noting that Kathy sent her text messages, which she referred to as a "veiled threat." She added, "You know, I don't do well with that kind of thing, Dorit."
In a confessional, Lisa read the text message Kathy sent her: "Please please do not say anything we discussed. Otherwise, it will make a huge scene that everyone gets dragged into." Additional messages were sent that read, "Please it goes further than you would want to know. Silence is golden. I am staying silent."
The two then discussed how Kathy went went on Instagram Live with E! and allegedly lied about the whole thing. She said that she wasn't screaming and throwing things, and that she was alone back at Kyle's Aspen house. Dorit confirmed to Lisa that Kathy admitted she lied when she said those things on Instagram.
Dorit and Lisa then joined the other women and the conversation continued. They said that Kathy wasn't herself that night and got upset when the DJ refused to play Michael Jackson's "Billie Jean" and that things devolved from there.
Sheree, 54, pointed out that Kathy was angry earlier in the day at Kemo Sabe, while Lisa had a moment of epiphany and realized Kathy got angry after she ordered Kendall Jenner's 818 Tequila over her brand.
"Kathy is so f---ing jealous of the Kardashians," she exclaimed in her confessional, claiming that was what set Kathy off. She then talked about the various things Kathy allegedly said about the women but in the group setting, she said she wouldn't divulge the details.
Tommy Garcia/Bravo/NBCU Photo Bank via Getty The cast of The Real Housewives of Beverly Hills season 12
When pressed by Sheree, Lisa didn't deny that Kathy had something to say about each of the women.
"Kathy spoke about all of these women. Some, she lumped together. Crystal, Sutton… 'Pieces of s---' and 'they should be fired. Like, why are they even here?' What she said about Dorit is that she was a stupid, useless idiot. It's a barrage of 'I f---ing can't believe that I have to be around you f---ing pions! I don't like them. Why do I have to be with them? They need to go away. They're idiots. I have to do everything around here. This is my show by the way. I have big deals over at NBC. Everyone is protecting me and I will f---ing ruin Kyle.'"
In her confessional, Crystal claimed Kathy admitted to her that she lost her temper — but when asked by a producer who she believes, Crystal took Kathy's side over Lisa's.
Kathy later went to Kyle's to apologize, wearing a T-shirt with the word "peace" written in large letters across the front — a shirt Lisa would eventually point out was the same shirt she wore during her tirade in Aspen.
Kyle confirmed this was the first time the two had seen one another in person and that they'd only exchanged a few brief texts since their fight. Kathy was emotional and expressed her desire to make amends. Then, there was a series of flashbacks to past reunion shows as the sisters made amends from past fights.
"When these things have happened in the past, it affects me tremendously," an emotional Kyle said in a confessional. "Nothing can get my anxiety going worse than having that conflict with my family and having to sort of keep it to myself."
"What I want to say is that I'm here to apologize to you," a genuinely remorseful Kathy began. "I started ranting and venting my feelings and I didn't think that they would get back to you."
Araya Diaz/WireImage Kathy Hilton and Kyle Richards
Kyle then called her out for treating her poorly that night in front of the group. "It really hurt me and embarrassed me," she said.
Kyle pressed, wanting to know why she said such hurtful things, and Kathy blamed the altitude and too much wine. At that, Kyle got choked up.
"I don't feel like I've had a lot of support from my sisters for, I don't even know, for a very, very long time," she said while attempting to fight back tears. "And when I hear you talk like that, the things you said, I feel like you hate me or something. If someone hurts me I have to keep them at arm's length to protect myself. Blood included."
Kathy apologized and told Kyle how proud she is of her and the two hugged and appeared to make amends. Kyle opened up more in her confessional about the loss of her parents and how important it is to have her big sister in her life.
"My mom and my dad were always my biggest cheerleaders and when you lose that, you kind of feel like no one's ever going to love you like that. And no one's ever going to support you, be proud of you like that," she said. "I think hearing Kathy say that you know, she is my big sister. Because I don't have my parents, you know, hearing her say that obviously means a lot to me but it completely contradicts what she said in Aspen. So, what do you believe?"
Jason LaVeris/FilmMagic Kathy Hilton, Kim Richards and Kyle Richards
Lisa then came over and joined the conversation but refused to back down to Kathy or listen to any excuses, even as Kathy profusely apologized. "You know, I was really shook," Lisa said. "I've never seen anything like that."
She urged Kathy to take a look inward and try to understand what triggered her. Kathy said she doesn't usually have a temper but admitted she did that night. Lisa then told her she was cruel with her words.
"I feel if we're really going to talk about this, you're going to have to take responsibility for some of the things that you've said," she told Kathy. "You said some things about everybody. Not just Kyle. Like, big f---ing things. I don't want to say that you need help, Kathy, but I think you need some help."
Kathy defended herself and argued that Lisa can also be unkind. "Oh, we're going to go there," Lisa replied. "It's not about me right now. This is about you."
Kathy cried over a friend dying of cancer — but even then, Lisa would not let her off the hook.
"I'm sorry, Kathy, you're not going to get away with it with me," Lisa said. "You can have your tears. You can do what you're going to do but you did what you did and you're not going to just gaslight and manipulate me right now. If you want to apologize to me, let's talk about what you really did and let's talk about some of the names you called people and we'll go there if you want to."
Lisa then told Kathy she locked herself in her bedroom that night "because you were having a psychotic break of some kind. Like it was really out of control."
Kevin Parry/WireImage Lisa Rinna and Kathy Hilton
A flashback to a past fight between Lisa and Kyle and Kathy's sister Kim was then shown, featuring an out-of-control Lisa throwing and breaking a wine glass at a lunch and screaming at Kim to stay away from her husband.
It was clear a resolution was nowhere in sight — but Lisa made sure to get the last word in.
"I just want to know where that hatred comes from. You gotta figure that out. You've got to figure out why you have a black heart. What is it?" she asked.
In a teaser for next week's finale, Lisa continues to push the issue and Kyle makes it clear she's uncomfortable and that she's moving on. The women speculate there might be a mole in the group and wonder how certain details this season have been leaked to the press. Kyle goes so far as to say there seems to be a crusade against Kathy. Blood, it appears, will always be thicker than water. There have also been hints that some cast members will not be returning next season.
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The Real Housewives of Beverly Hills airs Wednesdays at 8 p.m. ET on Bravo.