In July, R. Kelly was arrested on federal charges alleging sex crimes and obstruction of justice. 

He was originally facing 18 counts.  But the Feds have added at least one more and it involves his notorious relationship with the then-underage Aaliyah.

According to documents obtained by TMZ, the Feds say that on August 30, 1994, Kelly and others paid money to a public official for "the creation of a fraudulent identification document for Jane Doe #1 [Aaliyah.]"

The next day Kelly secretly married the 15-year-old Aaliyah using an ID claiming she was 18. According to the new charge against Kelly filed 25 years later, he commitment bribery by paying for the fake ID. 

Kelly's lawyer Doug Anton pushed back against the added charge, saying it "is ridiculous and it smacks of the same desperation as the entire case."