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Kim Richards fell off the wagon at her daughter's wedding just days after leaving rehab, according to a new report.

While attending her daughter Brooke's wedding in Mexico, "The Real Housewives of Beverly Hills" star "melted down" to the point that her sober coach quit and her daughter isn't speaking to her, TMZ said.

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The website is reporting that Kim was clearly under the influence of either drugs or alcohol at the wedding. Kim was also apparently saying "horribly nasty things" to her daughter, prompting Brooke to cut off all communication.

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"Whatever Kim took or drank, she did so in private, but when she interacted with people at the wedding she was a mess," TMZ said.

No one seems to know what Kim took, whether drugs or alcohol.

RELATED: Kim's family finds her situation "heartbreaking"

Kim was allowed to leave her rehab facility to attend the wedding but she was supposed to return by May 25, but she is nowhere to be found.