Rachel Bilson Gives Mischa Barton the Sweetest Dancing With the Stars Shout-Out

Although it's been eight years since The O.C. went off the air, Summer Roberts and Marissa Cooper's friendship is still going strong. Rachel Bilson, who played the adorably sassy Summer on the hit show, gave former costar Mischa Barton the sweetest shout-out via Instagram on Monday night after watching her first appearance on Dancing With the Stars. After Mischa bravely danced a tango with partner Artem Chigvintsev, Rachel posted a screenshot of the show, writing, "Got to give it up for @mischamazing takes balls. Get it guurrrrlll!" See her cute snap above, and then check out Jodie Sweetin's sultry performance!