Three days after Robin Williams' tragic death, his wife reveals the star was battling the early stages of Parkinson's disease.

“Robin spent so much of his life helping others. Whether he was entertaining millions on stage, film or television, our troops on the frontlines, or comforting a sick child — Robin wanted us to laugh and to feel less afraid," Susan Schneider shared in a new statement.

"Since his passing, all of us who loved Robin have found some solace in the tremendous outpouring of affection and admiration for him from the millions of people whose lives he touched," she continued.

"His greatest legacy, besides his three children, is the joy and happiness he offered to others, particularly to those fighting personal battles."

robin williams

Robin and wife Susan in April 2012

Susan confirms that although the 63-year-old's sobriety "was intact," he struggled "with his own battles of depression, anxiety as well as early stages of Parkinson's Disease, which he was not yet ready to share publicly."

According to the Mayo Clinic, Parkinson's is a "progressive disorder of the nervous system that affects your movement."

Symptoms vary between patients, but can include tremors, slow movement, rigid muscles and speech changes. Given Robin was in the early stages, his symptoms were most likely mild.

"It is our hope in the wake of Robin's tragic passing, that others will find the strength to seek the care and support they need to treat whatever battles they are facing so they may feel less afraid,” Susan added.