Justin Bieber -- BUSTED IN CALABASAS ... You're Not Licensed to Drive Here

Justin Bieber was pulled over in Calabasas this morning for driving like an a-hole -- and during the stop, cops discovered the pop star shouldn't have been on the road in the first place ... 'cause he's NOT licensed to drive in California, TMZ has learned.

Law enforcement sources tell us ... cops noticed Justin's white Ferrari blowing through a stop sign near his Calabasas home around 4:30 AM Wednesday morning.

We're told Justin was cooperative during the stop -- but cops noticed that JB did not have a valid California driver's license, something new residents of the state are required to have within 10 days of moving to CA.

FYI -- Justin bought his Calabasas home at the end of June.

Sources say Justin was cited for running the stop sign and for driving without a valid California License. JB was ordered to get out of the driver's seat -- and his passenger was allowed to drive the car home.

If Justin wants to get back behind the wheel -- he'll be required to hit up the DMV first and obtain the proper CA driver's license ... and if he wants to make that happen by the end of the day, he should probably get in line now.

Calls to Bieber's reps have not been returned.