Inside Bethenny Frankel's Birthday Bash: Reality Star Parties Will RHONY Castmates—and Major Drama Goes Down!

Bravo star is returning to the hit franchise for season

Bethenny Frankel celebrated her birthday in true Real Housewives fashion last night. 

The Bravo beauty, who is officially returning to the Real Housewives of New York for season seven, rang in the big 4-4 on Thursday night at NYC hot spot The Monarch Room, where she celebrated with her RHONY castmates, including Carole Radziwill, Heather Thomson, LuAnn de Lesseps, Sonja Morgan and Ramona Singer, as well as boyfriend Michael A. Cerussi III. 

"Everyone arrived by 9 p.m. The cast was ushered upstairs into a private room for filming," a source tells E! News. "Producers had the room guarded off while, downstairs, everyone was buzzing there must be major drama going on."

While it's unclear what went down between the ladies, a resolution was seemingly reached around 11 p.m., when the group headed downstairs to dance. 

"At that point, Bethenny's boyfriend had arrived and the two took over the dance floor," the source says of the pair, who coupled up back in January 2014. "They were kissing and seem very much in love." 

Ramona, who announced in August that she's leaving her husband, Mario Singer, and BFF Sonja were certainly enjoying the party as well and were both seen getting cozy with handsome younger men. 

"Sonja was openly making out with a guy who easily looked 20 years younger than her," the insider reveals. "Ramona was spotted chatting things up with a handsome young admirer, too. They left together."  

Meanwhile, Carole, Luann and Heather boogied down while snapping selfies. "Everyone looked great and seemed to be having a blast," the source dished. 

Frankel, who is an original NYC Housewife, famously exited the hit franchise in 2010 and went on to earn two Bravo spinoff series titled Bethenny Getting Married? and Bethenny Ever After as well as her own talk show (although it was canceled in February after just one season). 

Following the announcement, Bethenny explained in a blog post on her website why she decided to "return to my roots" on the reality series after "many years of hesitation." 

"Bravo and I have maintained an incredible partnership and relationship over the years, which is something I am very proud of and grateful for," she wrote. "It really is where it all began for me, and you can't forget where you came from."

"I have been through a long and arduous road since my departure," she continued, "and I'm finally coming out on the other side. It finally feels right to go home again."

She explained that "the idea of doing the show feels exciting and refreshing, like it did at the beginning," adding that she's looking forward to seeing, "New faces, new circumstances, and in many ways, a new me and a new life."

The forthcoming season of the Real Housewives of New York will feature returning faces Carole Radziwill, Heather Thomson, Kristen Taekman, LuAnn de Lesseps, Sonja Morgan and Ramona Singer in addition to Frankel. Aviva Drescher, who infamously threw her prosthetic leg on last season's finale, is not expected to return.

(E! and Bravo are both members of the NBCUniversal family.)