Dianne Holechek -- Chuck Norris' high school sweetheart to whom he was married for several decades -- has died ... TMZ has learned.
We spoke with Dianne and Chuck's son, Mike Norris, who tells TMZ ... Dianne passed away peacefully at her home in Texas after a long battle with dementia.
Mike says, "We are thankful she is no longer suffering. She was the best, the greatest mom. We were so lucky to have her.