Brigitte Nielsen Hospitalized -- Hit By Suspected Drunk Driver

"Rocky IV" star Brigitte Nielsen was rushed to the hospital after a 3-car smash-up in L.A. last night -- and cops believe the person who caused the wreck was driving while hammered.

Law enforcement sources tell TMZ ... Nielsen was a passenger in a 2006 Porsche Cayenne ... which was struck from behind around 10:20 PM by a woman driving a Toyota Matrix.

We're told the Porsche was knocked forward ... striking the car in front of it.

Cops and paramedics were called to the scene -- and the Matrix driver was arrested for DUI. Sources tell us the woman blew WELL ABOVE .08 on a breathalyzer test.

Nielsen -- who sustained injuries to her neck and back -- was transported to a nearby hospital, where doctors performed X-rays.