Ray J Sued by American Express for Unpaid Balance of $78K

Ray J's always lived large ... but now American Express is going after him in court, claiming the singer owes the company tens of thousands of dollars.

AmEx is suing Ray J for breach of contract and asking a judge to award the company $78,704.56 ... claiming he didn't pay back the balance on a credit card.

American Express is also suing Rajun Cajun Inc. ... a business allegedly connected to Ray J -- though it's unclear how. Sources close to Ray J tell TMZ ... he plans to pay off the debt.

This isn't the first time Ray J's been sued by American Express for alleged missed payments.

Back in December, the company claimed he owed $139,849.85. At the time, American Express also sued his company Tronix Network.

Between these lawsuits and Ray J's ongoing lawsuit with Kris Jenner and Kim Kardashian ... it seems Ray J may be locked up in court proceedings for a while.