Will.i.am -- CAR MYSTERY SOLVED ... $900K Ride Is Mine!!!

Here you have it ... Will.i.am IS the owner of that crazy $900,000 Dick Tracy-from-the-future car ... and to prove it, we got footage of him behind the wheel.

Photos of the ridiculous car surfaced yesterday -- and sources familiar with the all-aluminum ride told us it was built just for Will at the famous West Coast Customs (aka the "Pimp My Ride" people) ... but we were unable to confirm it with the rapper.

But now we don't have to ... because the rapper was driving it himself last week outside a fancy Italian restaurant in West Hollywood.

Vroom.