After over a year of negotiations, Tishman Speyer has closed on the long-term lease of the top six floors of the historic Morgan North Post Office by Hudson Yards.

The company intends to redevelop the massive 10-story building into high-tech creative office spaces with a 2.5 acre roof deck, eighth-floor terrace and other roof amenity space. Its original negotiations were first reported by the Real Deal.

The full-block Chelsea building is bounded by Ninth and Tenth avenues, West 29th and West 30th streets and is being leased for the next 99 years from the US Postal Service. USPS will continue to use the lower floors of the 1933-era building, which are connected to its Morgan South facility across West 29th Street.

Ceiling heights range to over 17 feet. The 620,000 square feet includes two floors of over 200,000 square feet each, while the 78,000-square-foot seventh floor will open onto the roof deck. Three upper floors each have 48,000 square feet.

Tishman will also have 5,100 square feet of retail on Ninth Avenue along with dedicated lobbies and elevators for up to three different tenants.

Sources said Tishman, led by CEO Rob Speyer, will be paying rent of $19 million per year to start, while tenant leases will hover around $100 per square foot.

Darcy Stacom and Bill Shanahan of CBRE represented USPS in the transaction.

The project is scheduled to open in 2021 and, as we told you in August, is already being touted to the companies like the FANG firms that include Facebook, Amazon, Netflix and Google.

Tishman could also lure the advertising giant, Dentsu, which, as we told you last week, has likely been bumped by Facebook from Vornado Realty Trust’s nearby Farley Post Office renovation.

Tishman is also developing The Spiral, a brand-new Bjarke Ingels-designed tower at the nearby 66 Hudson Blvd. on West 34th Street, where Pfizer will move.