Why Marissa Cooper was really killed off The O.C.

Actress Mischa Barton starred as Marissa Cooper on the hit television series The O.C.

The series creator of The O.C. has admitted that he still struggles with his decision to kill off Marissa Cooper.

Josh Schwartz joined other members from the show's creative team at the ATX Television Festival on the weekend where he was asked about the character's shocking death at the end of season three in 2006.

"It's complicated," Schwartz said while trying to explain why they decided to kill off Marissa, who was played by Mischa Barton.

"There were a lot of factors involved and it was something we really wrestled with. There were reasons both creative and just in terms for the show itself and where we were with the network."

The cast of the TV show, The O.C.

The TV producer, who later created Gossip Girl, said the decision is "something we still wrestle with".

In the season three finale, Marissa died in Ryan's (played by Benjamin McKenzie) arms after the pair were involved in a car crash.

The character's death divided fans of the show, which aired from 2003 to 2007.

"There were some people who celebrated and at the time, those were the most vocal people," Schwartz said.

But not everyone was happy to see the back of Marissa Cooper.

"There was a lot of anger and fan art that came our way," Schwartz admitted.

The series creator also told fans at the festival why he gave the role of Marissa to Mischa Barton instead of Olivia Wilde who also auditioned for the part.

"Marisa was obviously a character who Ryan needs to save," Schwartz said, "And Olivia Wilde needs no saving. She's pretty tough".

Here are some fun facts about The O.C.:

Josh is Seth: Josh Schwartz loosely based the character of Seth Cohen on himself. Schwartz, like Seth, was a bit of a loner growing up, particularly when he attended the University of Southern California after finishing school. "There were all these gigantic, blonde, water polo guys and their volleyball girlfriends and I was this shy Jewish kid going, 'What?'"

Adam Brody blew it: The show's creator Josh Schwartz hated Adam Brody (who played Seth Cohen) when he auditioned for the show. "When he first came in to audition, it was pilot season and he was going on dozens of auditions, and he didn't really bother to learn the lines, so he just came in and I was like, 'What scene is he doing? Is this even from our show?' Schwartz said.

A scene from the TV show, The O.C.

"We tried to find other actors, and our casting director, Patrick Rush, told me, 'I'm telling you, this Adam Brody is very special.' And I thought, 'That guy? I kind of hated that guy. He didn't even learn any of the words!' But he came back, learned the words, and he was great."

Shallow: Ever wonder why you never saw Seth or Ryan dive into the pool in the Cohen's backyard? Because it was so shallow the actors had to walk on their knees when they filmed a pool scene.

Brody hates boats: In the show, Seth Cohen was an avid sailor, but in real life, actor Adam Brody hated boats. According to Josh Schwartz, Brody agreed to film a scene on a boat for the pilot episode, but it didn't go very well. "He was green, he was just so miserable," Schwartz said. After that experience, Brody made Schwartz promise that he'd never ask him to film a boat scene again. So when the script required Seth to get on a boat once more at a later point in the series, they got a 45-year-old stunt double to wear a wig and film the scene instead of Brody.