Brandon Davis was arrested last night for battery and possession of a controlled substance -- after a physical altercation in Hollywood with a regular roundtable guest on "Chelsea Lately."
Cops were called to the Roosevelt Hotel after Brandon allegedly punched comedian Ben Gleib in the face. We're told Davis was denied entry to Beacher's Madhouse beforehand for his erratic behavior.
When police arrived, they searched Davis and found drugs, which law enforcement sources tell us was cocaine.
Davis was arrested for battery and possession of a controlled substance -- a felony -- and is currently being held at the Hollywood Police Department.
And here's a throwback -- Brandon's infamous Lindsay Lohan "firecrotch" diatribe from 2006 ... because WHY NOT?!
UPDATE: Brandon was just released.