R&B diva Mary J. Blige is singing the money blues after she allegedly defaulted on a $500,000 Bank of America loan, according to a new lawsuit.

The 41-year-old Blige — whose album sales have topped 50 million — took out the loan in 2005 and made payments through June 2011, when she abruptly stopped, the Manhattan Supreme Court suit claims.

The soulful singer now owes more than $511,000, which includes a $497,000 unpaid principal plus interest, court papers charge.

The Bronx-born recording queen has reportedly defaulted on sizable loans in the past.

Reps for Blige did not return phone calls.