Katie cassidy
Credit: Getty Images

Katie Cassidy, also known as Gossip Girl's Juliet Sharp, debuted a fresh brunet look during New York Fashion Week, an update from her ultra-sunny blond color. “I'm about to shoot a film, so I switched it up,” she told us at the Tracy Reese fashion show. “I feel a bit more mysterious and sexy, but I also think people react to me differently. In a way, they almost take me more seriously as a brunet then as a blond!” The expert colorists at the Valery Joseph Salon in New York City were responsible for the new hue. And Cassidy isn’t the only one going darker for fall—Julianne Moore also recently traded her ginger hair for a darker 'do. See who else dyed their hair this year in the gallery!

Sharon Clott, with reporting by Lindzi Scharf