TMZ has learned the LAPD arrested Patrick Disney Miller early Wednesday morning at his home in the San Fernando Valley.
Cops tell us he was booked for possession of a firearm by a convicted felon or addict, and for owning ammunition.
Patrick is the youngest son of Diane Disney Miller.
So far no one's anted up his $70,000 bail.
UPDATE: Patrick was finally released at 9:44 PM PST last night.