"We're going to celebrate new transitions, new beginnings," Singer said about the party she was throwing for herself to celebrate her divorce and start of a new life. "It's about me being me."
"New beginnings?" Frankel retorted when greeted at the door by Singer. "What does that even mean? That sounds like a bunch of bulls---."
The pair continued their feud that started during Sonja Morgan's fashion show when Frankel told Singer she was miffed that she not only "stole two dresses" from her former talk show but also because she had learned that Singer had told people that Frankel had cheated on her first husband.
"Sometimes when you have a 4-year-old they slap you but they don't realize what they've done," Frankel told her. "You can't be mad at a 4-year-old."
"Sometimes I'm like a 6-year-old," Singer agreed, before Frankel said, "You're giving yourself two years."
Continued Frankel: "I think you should be honest and not an ass---- and then package it in pretty paper the next day."
"Let's talk about it later," said Singer, who left.
RHONY Star Bethenny Frankel Responds to Critics about Her Being Too Skinny
But Frankel wouldn't let it rest, telling her "everybody at this party is going through a lot" and essentially forcing her to apologize.
"I was wrong and I never should have said it," Singer finally said. "The old Ramona would never have apologized but I'm a new Ramona and we can get over this quickly."
But The Countess and Carole Radziwill couldn't settle their squabble that fast, as the two battled over boys.
"She was trash-talking Adam and I," said Radziwill, who brought her young boyfriend to the party – a 20-something who not only used to be the LuAnn de Lesseps' chef but also the former boyfriend of her niece. "LuAnn is so fake … she's a hypocrite and passive aggressive."
"Seeing Adam makes me ill," said de Lesseps. "I feel like I was hoodwinked. He was dating my niece."
"He's a single guy, and I'm single," said Radziwill, who then discovered the Countess was actually more upset that she didn't stand up for her during the now-infamous be cool, don't be like all uncool girls' trip to the Turks & Caicos in which a naked man was discovered sleeping in the room next to Heather Thomson.
"There could have been a guy in my room," the Countess whispered to her. "How would that have looked to my son?"
"I've got an idea. Don't bang random guys on vacation," said Radziwill.
"She broke the girl code," said de Lesseps.
"It's like one dig after another," retorted Radziwill. "And that maniacal laugh."
The maniacal laughter continues on part one of The Real Housewives of New York City reunion, airing Tuesday (9 p.m. ET) on Bravo.