'Bold and the Beautiful' Star Winsor Harmon Arrested for Drunk in Public

This one's bold, but it ain't beautiful -- Winsor Harmon was arrested after allegedly getting loaded in his car and peeing in front of a live audience ... TMZ has learned.

Law enforcement sources tell us the famous soap star -- who starred in "The Bold and the Beautiful" as Thorne Forrester for two decades -- was arrested last week in the San Fernando Valley after eyewitnesses allegedly saw him urinating at a park in broad daylight.

We're told cops were called to the scene and Harmon was found inside his SUV in the parking lot -- where officers saw empty wine bottles scattered about ... and Harmon without a pair of pants on. Sources say he admitted he'd stayed there overnight.

Cops arrested him for being drunk in public.

It's interesting ... Harmon had his iconic role as Forrester recast last year with actor Ingo Rademacher. Makes ya wonder if the soap woes seeped into reality.