1. Chris Pratt as Che
Chris Pratt may be blockbuster star but he too had his time in Orange Country. Pratt had a recurring role on the series playing Che, an activist at Brown University who befriended Summer Roberts.
2. Paris Hilton as Herself
Paris Hilton played a highly savage version of herself when the gang visited L.A. In the episode.
3. Paul Wesley as Donnie
The Vampire Diaries alum made a memorable two-episode stint as Donnie, the guy who shot Luke, in season one.
4. Nikki Reed as Sadie Campbell
After making a name for herself in Thirteen, Nikki Reed guest starred as Ryan's girlfriend, Sadie Hawkins, in season three.
5. Olivia Wilde as Alex
Olivia Wilde had a brief stint in the second season of the series as Alex Kelly, who runs The Bait Shop and enters into a brief relationship with Marissa Cooper.
6. Shailene Woodley as Kaitlin Cooper
The Big Little Lies star had played the younger version of Marissa’s sister, Kaitlin, who would later be played by Willa Holland. She recurred throughout the first season before she departed for boarding school.
7. Amber Heard as Shop Girl
Amber played a sassy salesgirl in Newport Beach who accidentally locked the gang in a mall overnight.
8. Ashley Benson as Riley
Years before Ashley Benson got her breakout role as Hannah Marin in Pretty Little Liars, played popular girl Riley, who had a fight with Kaitlin Cooper in Season Four.
9. Bella Thorne as Young Taylor
The former Disney Channel actress played a younger version of Taylor Townsend in a season four flashback.
10. Chris Brown
Chris made a brief appearance on the fourth season as Will Tutt, a lonely band geek who befriends Kaitlin Cooper.