Law firm Fried Frank is moving and expanding its midtown conference center from 375 Park Ave., the Seagram Building, to Park Tower Group’s 535 Madison Ave. The 15-year lease for 14,375 square feet is for the entire 10th floor.

The move in 2024 will give Fried Frank more elbow room than it had and eliminates the inconvenience of being on two floors.

“It’s a great building,” said Fried Frank real estate chairman Jonathan Mechanic, who was basking in the after-glow of his firm’s annual holiday party at Cipriani 42nd Street.

Fried Frank’s home base remains at One New York Plaza downtown. But Mechanic looked forward to the new uptown digs, which will have a bigger board room, more space for his attorneys — and access to the tower’s amenities including an outdoor plaza and first-rate art.

“[Park Tower chairman] George Klein has a great collection,” he said. “George and [company president] Marian Klein Feldt have their offices at 535 Madison so they treat the building like home.”

Long regarded as the real estate world’s No. 1 “fun” event, the party on Tuesday was Fried Frank’s first truly full-bore celebration since 2019.

Noshing and schmoozing under the cathedral-high ceiling were Empire State Realty Trust head Tony Malkin, Silverstein Properties CEO Marty Burger, RXR chairman Scott Rechler, Jack Resnick & Sons president Jonathan Resnick, Wharton Properties founder Jeff Sutton, JEMB chairman Morris Bailey, the Rudin development clan’s Bill, Michael and Samantha, Global Holdings Management chairman Eyal Ofer, Related Companies general counsel Alexis Kremen, Tishman Speyer managing director/development Valerie Speyer Peltier, Cushman & Wakefield’s Bruce Mosler and John Cefaly and Vornado president Michael Franco.

Also there: SL Green head of leasing Steve Durels, Citibank real estate head Tom Flexner, Morgan Stanley real-estate investment banking chief Seth Weintrob and Goldman Sachs real estate financing director Miriam Wheeler.

Klein Feldt celebrated with Rockefeller Group senior managing director Meg Brod over their companies’ joint-venture residential project in Greenpoint.

“I introduced them to one another and now they’re fast friends,” Mechanic said.

Klein Feldt celebrated with Mechanic, too.

“She brought the lease papers for 535 Madison, and we actually signed them at the party,” he said.