(Bloomberg) -- SL Green Realty Corp. said it’s seeing “very robust interest” from potential office tenants for its One Madison redevelopment project in Manhattan.

Term sheets are being exchanged with companies that are considering space in the tower, executives of the real estate investment trust said on its earnings call Thursday. SL Green is gutting and transforming the property overlooking Madison Square Park in the Flatiron district, and last year secured a $1.25 billion construction loan from lenders led by Wells Fargo & Co.

While it has no committed office tenants yet, SL Green said Wednesday that it signed Chelsea Piers Fitness to a 20-year lease for 55,780 square feet (5,182 square meters) of the project’s retail space. The landlord is counting on the gym -- known for its high-end facilities and personal training options -- to help pitch the tower’s offices. 

“It’s our number one amenity to market off of, and Chelsea Piers knows that and wants us to,” Chief Executive Officer Marc Holliday said on the call. “We want to use that as an example of the best-of-the-best kind of tenants that will be attracted to One Madison.”

SL Green also announced the opening of the observatory at its One Vanderbilt skyscraper near Grand Central Terminal, offering views of the city from 1,210 feet (369 meters) above ground. That office tower debuted in September 2020 and is now more than 90% leased.

“The level of large-scale tenant interest at One Madison is much earlier to the game than it was at One Vanderbilt,” Chief Financial Officer Matthew DiLiberto said on the call. “We have a very robust tenant interest.”

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