Rachel Bilson was born August 25, 1981 in Los Angeles, CA. At the age of seventeen, Bilson took her father's advice to pursue a career in acting, and soon landed a few commercials. In 2003, Bilson made her acting debut appearing in Buffy the Vampire Slayer, 8 Simple Rules for Dating My Teenage Daughter, and in the short film, Unbroken. Later that year, she was cast for The O.C. as Summer Roberts. Summer's character was initially intended to last only a few episodes, but she soon became a regular. Summer Roberts is the daughter of Dr. Neil Roberts and girlfriend of Seth Cohen. Summer was best friends with Marissa before she died.