In a four-minute clip, that has since made its rounds on social media, Garcia and Darnell flung scathing insults at each other over what occurred at Angie Katsanevas’ Greek Easter celebration.
Darnell accused her daughter of not "playing nice" with the other women on the hit Bravo series.
"The only thing that you did was unite those four a-------, that’s the only thing that you did," she added, appearing to refer to fellow cast members Lisa Barlow, Meredith Marks, Heather Gay and Whitney Rose.
"How can you forget that your job is to get on air time, to get into as many scenes as possible?" Darnell continued, telling her she just needed to be an "actress" and "pretend like all is right in the world."
Garcia shouted back that her mom left her "completely in the f------ water with these b------" before calling her a "f------ mess" and telling her she "f----- it up yesterday."
"You are insane, you looked like a crazy person just so you know," the 40-year-old ranted, going on to call her mom "disgusting" and "gross" and screaming at her to "get the f--- out of my house!"
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The RHOSLC star later took to her Instagram Stories to allege her former best friend, Tanesha Luckett, had been responsible for leaking the shocking video of their fight.
"There has now been a ‘leaked’ private video filmed in my home between my mother and I. I sent the video to my best friend. In confidence," she said on Wednesday, January 3. "I never once thought she would do this to me, but here we are. She has been outting [sic] my secrets, she continues to release screenshots, recordings, videos, a folder she has dedicated to me full of things she plans to release."
"This is a full blown takedown by one of my once closest friends that my girls and I considered family. Brace for impact because she has a 3 year friendship of information."
This comes after Gay exposed Garcia for allegedly living a double life as a Housewives gossip blogger.
"Monica is not who she says she is," she declared in the RHOSLC Season 4 finale. "She's not our friend. She's someone who has schemed and worked to infiltrate our friend group, and the name that you all know her as — the woman whose birthday we celebrated, who we have been trying to champion and support and defend — is Reality Von Tease."
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A source spilled to an outlet that the show's casting team and producers had no idea that Garcia had been associated with the Instagram account.
"While they were aware of her connection with Jen Shah, they were completely unaware of the information that Heather discovered in Bermuda," the source shared. "Heather's revelation came as a surprise to the producers, much like the unexpected FBI visit at the Beauty Lab & Laser parking lot during season 2 involving Jen."
The source spoke with ET about production knowing nothing about Garcia's online identity.