EXCLUSIVE: 'Real Housewives of New York' Star Dorinda Medley Fires Back at Sonja Morgan's 'Hilarious' Drug Use

The co-stars got into it on part one of the season eight reunion.

Dorinda Medley is firing back at her Real Housewives of New York co-star Sonja Morgan.

On part one of The Real Housewives of New York season eight reunion, Sonja shouted, “Everybody knows you do drugs!” at Dorinda. The topic came up when castmate Bethenny Frankel admitted to referencing cocaine use while talking about Dorinda’s boyfriend, John Mahdessian.

WATCH: Luann de Lesseps Accuses Bethenny Frankel of Being a Mistress

“I'm not here to ruin people's lives,” Bethenny said, attempting to shut down the drug talk. “I'm not here to f**k with people.”

“Why are you insinuating that you know I do drugs?” Dorinda asked. “That's a horrible thing.”

That’s when Sonja made her claim, which Dorinda staunchly denied. Dorinda said it would be impossible for her to have a cocaine habit, noting that she lives full-time with her 22-year-old daughter, Hannah. She reiterated that same defense to ET when we caught up with the reality star at her home in the Berkshires.

“Listen, I think it's hilarious,” Dorinda tells ET. “I think poor Sonja's trying to be relevant … The truth is, I didn't film with her at all this season. I think I had one scene and I don't really see Sonja all season. So, you know, she's just trying to be relevant.”

“Poor Sonja had to run with something,” Dorinda continues. “What does she have? I mean, consider the source. You know?”

WATCH: Bethenny Frankel Is 'Distancing' Herself From Real Housewives of New York

“[John and I have] never again gone out with Sonja,” the 51-year-old says. “I don't know anything about her life. I never knew Sonja before the show, either … I’d heard of Sonja. I heard about her years of dating wealthy men and her antics, but we don't know each other.”

ET also caught up with Sonja at her home in New York City, where she stood by what she said on the reunion.

“That's not a denial,” Sonja says after hearing what Dorinda told ET. “That's 'check the source.' That's called deflection … My response is, everyone knows Dorinda does drugs.”

More drama goes down this Wednesday night at 9 p.m. ET on Bravo when part two of The Real Housewives of New York City season eight reunion premieres. Ramona Singer told ET the three-part event is “off the rails.” Hear more from her in the video below.