Mischa Barton is sharing her experiences — good and bad — on The 35-year-old actress spoke frankly about her character, Marissa Cooper's, shocking death on season 3 of the show and says that it was her treatment on set that led to the decision. «It started pretty early on because it had a lot to do with them adding Rachel [Bilson] in last minute as, after the first season, a series regular and evening out everybody's pay,» Barton told of Bilson's character, Summer Roberts.