Kelly LeBrock -- Arrested for DUI

Kelly LeBrock -- the gorgeous star of "Weird Science" -- was busted for DUI.

The arrest flew under the radar for more than 2 weeks, but we've learned the arrest occurred November 30 near Santa Barbara.

Law enforcement sources tell us a CHP officer spotted LeBrock -- who was married to Steven Seagal -- driving erratically, weaving across the double yellow line, failing to stop at a stop sign, and driving over the 55 MPH speed limit.

The officer said there were signs of alcohol impairment, and gave her a field sobriety test ... and LeBrock didn't do so well. She was arrested and booked.

Prosecutors have the case. No charges have been filed ... yet.

We called LeBrock's rep. So far ... no word back.