The actresses also looked great, both decked out in short strapless dresses and skinny-heeled pumps.
"The To Do List" follows Plaza's character, a high school valedictorian looking to ditch her good girl image and her virginity. She enlists the help of her big sister (Bilson) and her friends on her quest to cross off every raunchy activity on her summer sex to-do list. Connie Britton, Bill Hader, Andy Samberg, and Clark Gregg also star.
Check out the cute photos of the premiere below, and see Plaza try to lose "it" when "The To Do List" hits theaters this Friday.