The 214m-tall tower on Lexington Avenue has been given the go-ahead by the American National Landmarks Preservation Commission to exploit 'unused air rights' immediately east of the influential Mies building.
The soaring, slender building, which will house a hotel and apartments, is bound to provoke strong reactions from both local heritage groups and architectural connoisseurs around the world.
One of the key fears is the damage to the iconic views of the Seagram Building from Park Avenue.
It is also understood the Foster project has yet to get the final thumbs-up from the City Planning Commission, who will launch their own hearing into the scheme.
However, as part of the planning application, the developers RFR Realty have agreed to renovate and repair the existing Seagram Building.