The performer, 52, was arrested on Wednesday over the unpaid support for three children he has with Andrea Lee. The Cook County Sheriff's Office had said he would have to pay the full amount to be freed.
Sam Randall, a spokesman for the sheriff's office, said in a phone interview on Saturday that the source of the payment was unclear, noting that the name section of the bond slip was left blank.
"Anonymity in this situation is pretty rare," Mr Randall said. "Typically that section of the form is filled out."