Warner Bros. Studios / DC

Ron Dean , famous for his work on "Risky Business" and "The Breakfast Club," is dead.

The veteran actor died Sunday at a hospital in Chicago ... according to Maggie Neff , Ron's partner of 40 years.

The cause of death is unclear, but Maggie tells us Ron has been battling a long illness.

She tells TMZ ... "He passed at exactly 4 PM, after his beloved sisters had said their goodbyes. He hung on like a warrior to say goodbye to his little sisters. Then we were alone, and in my arms, I held his hand, and he trusted me when I told him that it was alright to let go. What an honor!" Warner Bros. Studios / DC

Ron often played law enforcement on the big screen and one of his first acting credits was "Risky Business," alongside Tom Cruise . He also worked wit

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