Pharrell Williams has apologized for wearing a Native American headdress on the cover of Elle UK’s July issue. The “Happy” singer and prolific music producer, who reportedly does have some Native American ancestry, is pictured on the cover wearing a warbonnet, a sacred headpiece reserved for chiefs and warriors.

The image instantly created backlash, spawning the creation of the hashtag #NotHappy on Twitter, with many fans complaining that the headpiece was too culturally specific and sensitive to be an acceptable costume. One user, @onceAPARNATime, posted, “why does the fashion industry insist on turning sacred cultural items into fashion props?”

Williams issued an apology to Buzzfeed, writing, “I respect and honor every kind of race, background, and culture. I am genuinely sorry.”

Williams is not the first celebrity to come under fire for wearing the traditional warbonnet or other Native American accessories. Stars such as Heidi Klum have been criticized for using Native American cultural clothing as “costumes.” The Indian County Media Network has collected a list of rock musicians wearing the war bonnet, although Williams is not yet been added.

Prior to this, Williams’ most famous headgear was a Vivienne Westwood Mountie hat, seen at multiple events including the Grammys.

Photo credit: Elle