Will.i.am's ride got boom boom pow'd in the Hollywood Hills Monday night -- according to law enforcement sources, bad guys broke into his Bentley and jacked over $10,000 worth of stuff.



TMZ has learned the Black Eyed Peas star made the shocking discovery himself and called the police to file a report. According to sources, the loot included jewelry and several of the singer's personal items.

We're told cops are hot on the trail of the bad guys -- and some of the stolen property has already been recovered.