Thanks to constant auditioning and a well-connected agent, Rachel Bilson reached new heights in 2003. She appeared in an episode of Buffy the Vampire Slayer and 8 Simple Rules... for Dating My Teenage Daughter before landing the lead role in a short film called Unbroken.
Thanks to this exposure, Rachel Bilson was invited to attend an audition for FOX's potential new hit, The O.C. The show was aiming to target the same audience as previously successful shows like Beverly Hills, and Melrose Place.
This was perfectly in line with Rachel Bilson's capabilities, whose youthful, vibrant personality and hoty look impressed the producers of The O.C. They cast her as Summer Roberts, best friend of Marissa Cooper (played by Mischa Barton) and spoiled beauty who personifies the "Valley Girl" stereotype.