R. Kelly has been charged with 11 more sexual offences, according to US media.
Court records reportedly show they relate to sexual assault and abuse of a minor aged between 13 and 16, and if proven carry far heavier sentences than the others he faces.
R. Kelly is reportedly due back in court in a week to face the charges.
Earlier this year the R&B artist was charged with 10 counts of aggravated criminal sexual abuse. He pleaded not guilty and has been released on bail.
If convicted on the earlier charges, which involve four alleged victims, three of whom were minors, he could face three to seven years in prison.
R. Kelly's lawyer Steve Greenberg said the latest charges did not relate to a new case.
"He was recharged in an existing case, same alleged victim and time (a decade ago) It changes nothing," he wrote on Twitter.
"These are the same conduct, just charged differently, same alleged victim, same time frame, same facts. We expect the same results."
Chicago Tribune reporter Megan Crepeau reports four of the new charges laid against him are the most serious felony class in the state of Illinois, and carry a mandatory six to 30-year sentence.
Four charges are for aggravated criminal sexual assault, two for sexual assault and five for aggravated criminal sexual abuse.
The Chicago Sun-Times reports the new charges date from January 2010.
Dozens of women have come forward over the years accusing the singer of abusing them.
In January a documentary series, Surviving R. Kelly, showed a number of alleged victims talking about their experiences. R. Kelly has repeatedly denied the claims.
He lost a civil court case, brought by a woman who accused him of sexual abuse, after he failed to appear at the Chicago court in April.