Stars you forgot were on 'The O.C.'

When FOX's "The O.C." first aired in 2003, it made stars of Benjamin McKenzie, Mischa Barton, Rachel Bilson and Adam Brody. Those guys, you remember — but during the four seasons the TV show was on the air, many other now-familiar faces graced the screen. Some had forgettable split-second appearances (like Amber Heard, Lucy Hale, Ashley Benson, Bella Thorne and Kat Graham) but others made more of an impact. Chris Pratt, for instance, was in nine episodes as Summer Roberts' uber-hippie college pal, Ché. Chris was hilarious as he helped Seth Cohen find his animal spirit. Along the way, he got naked and sang a song about polar bears dying. It's fair to say that after "The O.C.," Chris did quite well for himself. To mark the 10th anniversary of the final episode, which aired on Feb. 22, 2007, take a look at who else was on the show.

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Cam Gigandet

Long before he was in the "Twilight" franchise, Cam Gigandet was Kevin Volchok on "The O.C." for 15 episodes. Cam was a true bad boy and the volatile boyfriend of Marissa Cooper. He ended up cheating on Marissa and became Ryan Atwood's mortal enemy. He's also responsible for (spoiler alert!) Marissa's death. Cam was one of several "Twilight" stars who appeared on "The O.C."

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Olivia Wilde

Olivia Wilde actually played a pretty substantial role on "The O.C.," but one that you likely forgot about. She was Alex Kelly, the manager of The Bait Shop. Alex hired Seth Cohen to work there and the two became romantic — at least until Alex's female ex showed up (more on that later). Much to Seth's surprise, he learned Alex was bisexual. Alex then ended up falling for Marissa too (love triangle alert!). Olivia, of course, is now a respected actress known for "Vinyl," "House," "The Change-Up," "Alpha Dog" and way too many other things to even attempt to list.

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Shailene Woodley

Yes, THAT Shailene Woodley appeared on "The O.C." several times. The young future superstar actress played Kaitlin, a little girl who often played at the Cohen's house. She was seen several times during Season 1. She returned again in Season 3. Clearly, no one knew that that girl would go on to star in "The Fault in Our Stars" and lead the "Divergent" series.

George Lucas

Mr. "Star Wars" himself, George Lucas, appeared on "The O.C." in 2005. He played himself (naturally). George put Seth Cohen into quite the predicament when he expressed interest in Seth's graphic novel and wanted to meet for dinner. Why the predicament? Well, the dinner was the same day as the prom, so Seth was forced to choose between taking Summer to prom or having dinner with George. He asked George for advice, and George told Seth he regretted not attending his own prom. There was a reason George was there: His film "Star Wars: Episode III – Revenge of the Sith" was released a week after the episode aired.

Paris Hilton

Her name may have been different, but Paris Hilton sort of played herself on "The O.C." when she signed on for the role of an L.A. socialite for one episode in 2004. As "Kate," Paris was interested in Seth Cohen. They even shared a smooch! The character was a party girl who's secretly a real smarty pants. In real life, Paris is a legit businesswoman worth $100 million.

Chris Brown

Before he was a household name (for a lot of less-than-stellar reasons), Chris Brown was a character on "The O.C." C-Breezy played Will Tutt, a drummer in the school marching band who befriends and eventually dates Willa Cooper, Marisa Cooper's sister. (Willa Holland, by the way, went on to have tremendous success as Thea Queen on "Arrow.") Chris and Willa's romance lasted three episodes, which is an eternity by "O.C." standards!

Morena Baccarin

Perhaps this is where the love began? Benjamin McKenzie's real-life fiancée Morena Baccarin actually starred on three episodes of "The O.C.," although the two never filmed together. Morena played Maya Griffin, a woman who becomes embroiled in a battle of sorts between Sandy Cohen, her father and her dad's employee (who her character dates). Morena went on to land a major role on "Homeland" and starred opposite Ryan Reynolds in "Deadpool." She now stars on "Gotham," alongside Benjamin. The two are engaged and have a baby girl together.

Jaime King

Raise your hand if you remember Taylor Swift's real-life bestie on "The O.C." …Anyone? Jaime King starred on a 2005 episode called "The Return of the Nana." Her role was actually noteworthy. Seth Cohen and Ryan Atwood met Mary Sue (played by Jaime) while visiting their nana. Mary Sue and Seth actually competed in a televised dance contest and Mary Sue covered herself with whipped cream and asked Seth to lick it off.

Logan Marshall-Green

Logan Marshall-Green played Ryan Atwood's troubled brother Trey on Season 2. Trey's character was in prison for Season 1 but was released back into society. He tried very, very briefly to go the straight and narrow route, but he eventually found his way back to drugs and was even shot by Marissa. Logan has gone on to star on "24" and in "Prometheus" and "The Invitation." He'll next appear in Netflix's "Sand Castle" and Marvel's "Spider-Man: Homecoming."

Max Greenfield

He's now a lead on "New Girl," but on "The O.C.," Max Greenfield actually got the girl. The actor starred in a flashback scene in which he played a college-aged Sandy Cohen campaigning for 1984 presidential hopeful Walter Mondale at Berkeley. While supporting his candidate, he met Kirsten, who would go on to become his wife. He asked her to coffee, and the rest, as they say, is history.

Emmanuelle Chriqui

Emmanuelle Chriqui was "the ex" on "The O.C." The eventual "Entourage" star played Olivia Wilde's character Alex's ex-girlfriend (see, told you we'd get back to it). As Jodie, Emmanuelle stayed with Olivia's character in Orange County before heading back to Los Angeles.

Steve-O

Steve-O of "Jackass" fame couldn't escape "The O.C." either — well, he couldn't escape the show in Mexico! The funnyman played a drunk marine at a Mexican bar and filmed scenes with Adam Brody's character, Seth. Steve-O forced Seth to swill shots of tequila.

Nikki Reed

Another "Twilight" star living in "The O.C."! Nikki Reed starred on six episodes as Ryan Atwood's girlfriend, Sadie Campbell. Because of this, she was Marissa Cooper's rival. Nikki was already somewhat of a star before "The O.C.," based on her work in "Thirteen." The "Twilight" series, though, is where she really made her hay.

Colin Hanks

Colin Hanks appeared on the same episode of "The O.C." as Paris Hilton. His character, Grady Bridges, was the star of Summer Roberts' favorite soap opera. When he stumbled into the area, he ended up inviting his No. 1 fan to a party and tried to seduce her. Very serendipitously, Colin's big breakout role came in the film "Orange County." Colin doesn't have the credentials of his father, Tom Hanks, but he's been carving out a very successful career as an actor and rising documentary filmmaker.

Jeri Ryan

Already a favorite among nerds and the mainstream for her work on "Star Trek: Voyager" and "Boston Public," respectively, Jeri Ryan appeared on "The O.C." for seven episodes as Kirsten Cohen's friend Charlotte Morgan. They met in rehab. The two actually moved in together for a moment after Kirsten's rehab stint. Turns out, though, that Charlotte wasn't exactly a straight shooter and was really just trying to steal money from Kirsten… and anyone else she could hustle. Since "The O.C.," Jeri has continued to be an in-demand actress, mainly on TV.

Kevin Sorbo

On the final season of "The O.C.," Kevin Sorbo had a presence as Ryan Atwood's dad. Where'd he been the whole time? In prison, of course. Frank ended up falling for Julie Cooper and they had a son. While diehard fans of the TV show will always remember Kevin as Ryan's pop, he'll forever be known as "Hercules" to just about every other person out there.