The Black Eyed Peas star ranted on Twitter yesterday (August 14) after his DeLorean was taken from outside the Avalon hotel in Beverly Hills, which was staging a launch party for his new solo album.
"My car was stolen...what the f**k," he wrote. "Where is my f**king car...??? This isn't funny anymore."
will.i.am has since tweeted a YouTube video of a masked man with a manipulated voice mocking the Voice UK coach over the theft.
The individual, who goes by the handle 'willimnotanon', declares in the clip: "will.i.ain't, will.you.are, heard you're looking for your car.
"Did you look closer? Did you look far? Did you look in your cupboard? Did you look in a jar? will.i'm.not, will.you.are, ha, ha, ha, I stole your car."
In response, will.i.am threatened: "If you really have [the car] you going to be found..."
Other Twitter users have also been teasing the rapper by pretending to have found his car before sending him pictures of ridiculous novelty vehicles, including one plastered with cuddly toys and another shaped like a lobster.
will.i.am has stated on the site that he will not seek help from the authorities to find his car.
"Im not going to the police...spread the word via tweets in case I'm getting punk'd," he wrote. "I don't want to waste tax dollars on pranks #wheresmycar."