We saw Jessica Biel go darker a few weeks ago for her role in Powder Blue, and this weekend she showed her a polished version of her brunette look while hosting 3rd Annual Pink Party benefiting Cedars-Sinai Women’s Cancer Research Institute. Adir Abergel of Frederic Fekkai did Jessica’s hair for the event, showing off what he tells PEOPLE is a “modern shag. It’s the modern version of Jane Fonda’s haircut from Klute. The color is a rich auburn brown.” And Adir told us how he created Jessica’s low-key look for the event. He applied Frederic Fekkai Coiff Bouffant Lifting and Texturizing Spray Gel, $23 at sephora.com, all over the roots before rubbing a dime size amount of Controle Ironless Straightening Balm, $25 at sephora.com, all over her hair to the ends. Using a two inch round brush, he blow-dried all of her hair forward to frame her face with the cut’s heavy layers. To finish the look, he pieced out the ends with Coiff Nonchalant Piecing and Forming Wax to give it extra texture.