United Kingdom, Oct. 7 -- Saved by the Bell star Dennis Haskins died from Parkinson's disease.

The actor, who played Principal Belding in all four seasons of the NBC teen sitcom, passed away on September 27 at Providence Saint Joseph Medical Center in Burbank, California, at the age of 75.

While Dennis' death certificate, obtained by TMZ, identifies Parkinson's disease as the immediate cause, it also lists irritable bowel syndrome, depression, hypertension, and benign prostatic hyperplasia as other significant conditions.

The outlet reports that Dennis "spent his final years in an assisted-living facility" and cut off contact with his ex-wife, Sarah Quinones, and other close pals as he "didn't want anyone to know he was suffering from ...