Dorinda Medley Rips Into Tinsley Mortimer in RHONY Season Premiere: 'Just Tell the Truth!'

There was no love lost between Dorinda Medley and Tinsley Mortimer on Thursday’s Real Housewives of New York City season 12 premiere.

The two reality stars got into an explosive argument at a party Medley was throwing, each trading insults at one another while costars Ramona Singer, Luann de Lesseps, Sonja Morgan and Leah McSweeney looked on.

“You don’t know s—, shut your mouth,” Medley told Mortimer. “Kindergarten’s starting! You’re going to be late for the bus! You better go call mommy!”

She went on to boast about how she had bought her own shoes, claiming that she “didn’t have to lay on my back for them” unlike Mortimer. 

“You’re a jealous bitch,” Mortimer quipped back.

Their scuffle wasn’t much of a surprise for RHONY fans. Though Medley and Mortimer had been on good terms in the past, their friendship appeared to hit a wall at the end of last season, when Medley confronted Mortimer about her on-again, off-again relationship with now-fiancé Scott Kluth.

A bitter back and forth later came at the season 11 reunion, but didn’t seem to settle any ill feelings. In fact, Medley was only left feeling more convinced than ever that Mortimer was hiding things and not opening up to her costars.

“I just don’t know anything about her,” Medley said on Thursday, before meeting with Mortimer. “I couldn’t tell you what her favorite thing is. The minute you try to go deep at all, she retracts. She’s like the turtle!”

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Medley eventually brought those concerns directly to Mortimer. “It’s very important for the relationships as a whole, we can’t always be guessing, dragging, trying to pull out information from you,” Medley said. “Just be transparent about that! Just tell the truth!”

“This is not about Tinsley and Scott. It’s about transparency,” Medley told audiences. “There seems to be a lot of side game going on that we all find out about. I think Tinsley is a riddle that none of us are going to want to solve. We don’t know the answer, you win!”

“I don’t know if Tinsley has the ability to open up and be honest,” Medley also said. “We’re not cocktail party talkers, we’re bad bitches!”

For her part, Mortimer felt as though she was being honest. “Here’s the thing, I tell you the truth but you don’t want to listen to my versions of the truth,” Mortimer told Medley. “You’re calling me a liar. You’re calling me a liar!”

“I’m trying to tell you the truth and you won’t listen!” she shouted.

But Medley wasn’t buying it, telling Mortimer that other cast members felt that way before flipping out over the accusation that she was branding Mortimer as a liar.

“I didn’t say that. Don’t put words in my mouth. You ain’t going to be tricky with me. I will win every time,” Medley said. “I am tough!”

“You know what, so am I,” Mortimer snapped back. “I don’t give a s— what you think about that!”

“Is this you being tough a person? Because it’s failing,” Medley responded.

RELATED: RHONY‘s Dorinda Medley Admits to Being ‘Dismissive’ of Newcomer Leah McSweeney Because of Tinsley Mortimer

In the end, the two appeared to go their separate ways, angrier than ever.

“I’m done,” Medley said. “I feel like it’s fake, I’m sorry.”

“If I’m not talking to her about something, I’m hiding something. And if I try to pull her aside to have a private conversation, it’s fake. I guess I just can’t win,” said Mortimer.

The Real Housewives of New York City airs Thursdays (9 p.m. ET) on Bravo.