#nothappy@PharelI A little education goes a long way! A headdress is traditionally for a chief not a #chump
In a statement from his publicist, Williams apologised for the cover.
"I respect and honour every kind of race, background and culture," he said. "I am genuinely sorry."
Last month, the N.E.R.D frontman defended a group of Iranian youths who were arrested for posting a video of themselves dancing to his hit song, Happy.