R. kelly is in hot water again for allegedly falling behind on child support payments, and his own lawyer fears the R&B star, who has gone underground, could face jail time, sources say.

Kelly — whose latest album, “Black Panties,” debuted at No. 4 on the Billboard 200 in December as his biggest since 2009 — is accused in court papers filed Thursday by his ex-wife Andrea Kelly of failing to pay $20,833 a month in child support he owes. The claim comes after he reportedly fell behind more than $100,000 in payments last year, but then paid the debt off.

Kelly’s trouble doesn’t end there: One of his attorneys has told Kelly’s camp that if the singer doesn’t appear at a March 27 hearing in his child- custody battle in Chicago, a judge could give him 30 days to six months behind bars because Kelly didn’t show up at a November hearing.

“The judge was clear in November that he wasn’t happy R. Kelly didn’t show up,” said a source. “His lawyer [James Quigley] is worried the judge could lock Kelly up if he doesn’t show this time, but he can’t reach his client.”

Our source added that Quigley’s firm is owed thousands, itself, while it’s in custody negotiations with Andrea, a star of VH1’s “Hollywood Exes.”

Multiple sources say that despite his troubles, Kelly is “in a bunker” and “unreachable.” A source said Quigley’s firm may have to withdraw from the case if Kelly’s camp didn’t get in touch.

We reported the R&B whiz recently left top music firm Red Light Management for Devyne Stephens’ Georgia-based Upfront Megatainment. But now, “There’s a line of people Kelly owes money to who worked really hard on his last album,” another source said. “Who knows what Kelly and Devyne are doing, but burying your head in the sand isn’t the answer.”

Kelly previously has owed millions in unpaid taxes to Uncle Sam, and one of his homes was auctioned off this year. According to records, Stephens filed for Chapter 7 bankruptcy in 2012, which was denied, and was hit with five tax liens since 2004 that were paid off.

Quigley and Kelly’s reps did not return calls.