Williams has put the tall Vivienne Westwood-designed Buffalo hat, "a piece of pop culture history!" for sale on ebay.
Bidding for the hat, which comes with a "letter of authenticity," has already reached $10,500.
The “Happy” singer thinks the fast-food chain Arbys might be interested in putting in a bid. Pharrell tweeted on Thursday, "Hey @Arbys, you want my hat? Now's your chance."
All proceeds will go to Williams' kid-centric charity, From One Hand to Another. Williams also graces the March cover of Billboard magazine.
After all the attention it received, Pharrell Williams has decided to auction the funky hat he wore to the Grammys.