The long-underutilized ground-level space at 63 Madison Ave. (aka 28 E. 28th St.) has landed a huge retail tenant — Whole Foods Market, which signed for 60,000 square feet. The new gourmet emporium will have 10,000 square feet at street level plus 50,000 square feet on the second floor.

The 870,000-square-foot office tower is undergoing a major renovation by owners George Comfort & Sons, Jamestown and Loeb Partners — including a new, retail glass box on the first and second floors. George Comfort president Peter S. Duncan called Whole Foods “an ideal fit” for the property.

The landlords are also putting in a new office lobby and private outdoor spaces for high-floor tenants.

Facebook was in talks to take all the building’s office floors last year, but no lease was signed and no talks are going on. As The Post’s Lois Weiss first reported, CBS renewed on 164,000 square feet in April.

Whole Foods has added about 30 stores around the US since it was bought by Amazon in August 2017. It now has about 500 stores nationally including 14 in Manhattan, Brooklyn and nearby New Jersey.

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