A prank Ashton Kutcher tried to pull on hitmakers Black Eyed Peas turned ugly when the group's entourage started fighting with fake cops in a brothel.

Kutcher filmed the practical joke for his hit show PUNK'D, but he had no idea his victims would fight back.

Black Eyed Peas star WILL.I.AM was in on the prank, but even he was amazed by his bandmates' loyalty.

An eyewitness says, "Will.I.Am was an accomplice in the prank, but the rest of the band and their entourage became suspicious.

"When one of the cops acted like he was going to slap the cuffs on Will.I.Am, one of his friends punched a cop in the jaw."

The Punk'd crew hurriedly tried to explain the bust was a prank, but tensions were too high and no one was laughing.

It's not known whether the violent fight will appear on the show.

29/04/2004 09:00