EXCLUSIVE

Charlamagne Tha God is furious over new reports suggesting he sexually assaulted a teenage girl more than 17 years ago, since he was already cleared in a court of law ... and now he's lawyered up.

"The Breakfast Club" star's 2001 case is back in the headlines -- with his accuser now claiming she wants "closure" nearly 2 decades after officials dropped the criminal sexual assault with a minor charge against Char.

For the record, officials had always maintained that Charlamagne cooperated with the investigation and took a DNA test ... which did not produce any evidence that he had sexual contact with the girl.

Charlamagne did, however, plead guilty to contributing to the delinquency of a minor due to underage kids (including the accuser) drinking alcohol at the party he threw. He was sentenced to probation.

Now, Charlamagne -- real name Lenard McKelvey -- believes someone is dredging up the old case and fudging the facts in an effort to smear his name.

He's lawyered up with famed celebrity bulldog attorney Marty Singer and Michael Weinsten who tells TMZ, "More than seventeen years ago, Charlamagne was accused of a sexual assault. He never had sexual relations or any physical contact with the accuser and even provided DNA to prove it."

"At the time of these claims, Charlamagne cooperated fully with authorities, and after the investigation, this charge against him was dropped."

"Charlamagne has spoken about this many times over the years in public, including in his book. While Charlamagne has empathy for all sexual assault victims, he cannot take responsibility for a crime he did not commit.”