Singer-songwriter Mary J. Blige is in contract to sell her gated estate in the affluent New York City suburb of Saddle River, NJ, for a big loss, Gimme Shelter can reveal.

Blige bought the chateau-style mansion for $12.3 million in 2008; it was last listed for $6.98 million.

The buyer, we hear, is paying less than $6 million — less than half of what she originally paid for it. “Someone is getting an incredible deal,” says a real estate source.

Blige is a nine-time Grammy Award winner who is currently nominated for two Oscars — one for best supporting actress in “Mudbound” and the other for best original song in “Mighty River.”

Despite her successes, she has had financial issues. She currently owes millions of dollars to the IRS and pays a reported $30,000 a month in spousal support to her estranged husband, Martin “Kendu” Isaacs, according to reports.

The New Jersey estate at 119 E. Saddle River Road, just 25 miles outside midtown Manhattan, is approximately 13,000 square feet and sits on roughly 4 acres. It comes with eight bedrooms, 10 full bathrooms and three half bathrooms.

Taxes are $85,000 a year, notes the listing.

The home opens to a grand, double-story entrance foyer with custom tiled floors and woodwork. There are also two formal dining rooms, a custom bar, a library with a fireplace and a souped-up chef’s kitchen.

The lower level boasts a wine cellar with a tasting room, a movie theater, an indoor half basketball court, a gym with a sauna and steam shower, and a recreational room.

The master suite is regal, with vaulted ceilings and a separate sitting room with a woodburning fireplace. Its balcony overlooks the grounds, which include a pool and a pool house with its own bedroom, bathroom and kitchen.

Listing broker Joshua Baris, of Coldwell Banker, declined to comment.