Rachel Bilson Celebrates The O.C.'s 15th Anniversary with a Very 2000s Photo: 'Can't Believe It'

The O.C. is turning 15, and Rachel Bilson is looking back on the hit series that had Phantom Planet’s “California” on repeat in the minds of a generation.

Bilson, 36 — who shot to fame as Summer Roberts on the Fox show — posted a tribute to The O.C. on Instagram on Sunday, exactly 15 years after its first episode aired.

Her throwback picture shows cast members Mischa Barton, Adam Brody, Melinda Clarke, Peter Gallagher, Kelly Rowan, Ben McKenzie, and Samaire Armstrong rocking early 2000s fashion. Bilson is in the center of the snap, which also included EPs McG and Josh Schwartz.

“15 year anniversary of The OC,” Bilson wrote in a post liked by Glee alum Lea Michele. “I can’t believe it. I also can’t believe I wore a skirt I got at a thrift shop as a shirt #ifeelold #survivedtheschwartzsharkattack #welcometotheocbitch #ew.”

The cast of <em>The O.C.</em>
The cast of The O.C.

In June, Bilson gushed to PEOPLE about her time on The O.C., which ran from 2003 to 2007. “It was such a special time,” Bilson said. “The characters were really well thought out and there was so much chemistry between everyone.”

She shared a number of her favorite moments from the show.I laughed so hard with Chris Pratt,” Bilson recalled about Pratt’s appearance in season 4. “I remember laughing my a– off. He’s seriously the funniest person I’ve ever come across.”

The cast of <em>The O.C.</em>
The cast of The O.C.

She also got a kick out of her Spider-Man-inspired kiss with Brody, 38. “That was a fun one,” Bilson said. “Even now, there are moments from the show that I look back on and I’m like, ‘That was really cool!'”

RELATED VIDEO: Does Rachel Bilson Still Keep In Touch with The O.C. Castmates?

Bilson and Brody were an on-screen and off-screen couple before they split in 2006. Bilson now has a 3-year-old daughter, Briar Rose, with ex Hayden Christensen, and Brody is married to Leighton Meester, with whom he shares a 3-year-old daughter, Arlo Day.

RELATED: Rachel Bilson, Hayden Christensen Spend Time with Daughter After Split: ‘They Seemed Perfectly Civil’

In 2017, Bilson told E! News that she would be interested in reviving the show. “I’m always open to things,” she said. “I don’t know what it would look like with our characters being old now. We were riding skateboards on the pier; I don’t know what they do now as 30 year olds. But it would be nice to see everybody again.”