Usher, Sean Combs and Jessica Simpson are ringing in the holiday season with a new festive advertisement for U.S. department store MACy's. The pop stars join lifestyle queen Martha Stewart, Russell Simmons, Tommy Hilfiger and property tycoon Donald Trump for the colourful Christmas commercial, in which the celebrities all promote their perfumes, colognes, clothing, tableware and other treats - which are all on sale at MACy's. The stars help decorate the store in the ad and Simpson's famous dizzy reputation comes into play when she accidentally pulls the plug on the Christmas lights.