Mischa Barton and Nicole Richie are reportedly sharpening their claws in anticipation of a fashion face-off. The fomer OC star – whose wardrobe choices often come in for a good degree of flack – has been set to release a new head band range. But plans to give the line the go ahead have been brought to a stand still because fellow hippy head band wearer Nicole Richie plans to do the same for her House of Harlow. “Mischa is furious,” a source tells Star Magazine. “She feels like Nicole completely copied her idea.”