Robert A.M. Stern designing Chetrit’s Sony Building condos

The Chetrit Group’s much-hyped condo conversion of the Sony Building in Midtown is picking up steam, with the launch of the project’s teaser site that reveals several new details – including Robert A.M. Stern Architects’ involvement in the redevelopment.

The architectural firm, known for its work on high-end luxury residential projects like Zeckendorf Development’s 15 Central Park West and Silverstein Properties’ 30 Park Place, will design the tower’s condos, which will occupy floors 21 through 43 of the building.

The project — newly dubbed 550 Madison, after the Sony Building’s address — will also hold 113 condos, instead of 96 units as previously reported, according to Curbed.

Also previously reported and coming to fruition will be a hotel in the building operated by Germany’s Oetker Collection – the 170-key New York Masterpiece, which will feature 60 suites and amenities, such as a pool, spa and upscale restaurant, that will also be available to the tower’s condo residents.

The Chetrit Group partnered with frequent collaborator David Bistricer of Clipper Equity to acquire the 37-story property from Sony for $1.1 billion in 2013. Chetrit filed a condo offering plan for the building earlier this year.

A triplex penthouse at 550 Madison is expected to ask $150 million, as The Real Deal reported, while the tower’s second- and third-priciest units will look to fetch $75 million and $60 million, respectively.

The conversion, expected to open in early 2018, will be Midtown’s latest luxury hotel-condo redevelopment in the vein of buildings like Extell Development’s One57, which has a Park Hyatt hotel on its lower floors. [Curbed] – Rey Mashayekhi