Rachel Bilson
Credit: Eric Ryan/Getty; Seth Poppel/Yearbook Library

Happy Birthday, Rachel Bilson! The actress and InStyle contributor turns 30 today, and we're marking the occasion by taking a look at her beauty transformation! We first met the petite star on The O.C., and she has evolved into a red carpet staple ever since. Next up, we'll see her in the new CW show Hart of Dixie, premiering September 26th. See Bilson's evolution in the gallery!