Move over, Lauren Conrad! There's a new girl in town!

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Mischa Barton may be the only confirmed newbie joining the cast of MTV's "The Hills" reboot, but she's already getting chummy with some of the O.G. returning girls.

On Oct. 12, she took to Instagram to share a selfie with her new BFFs Audrina Patridge and Stephanie Pratt.

"On Wednesdays we wear whatever we want... and you can totally sit with us," she captioned the cute picture with an allusion to the 2004 high-school comedy "Mean Girls."

Stephanie, whose brother Spencer Pratt and his wife Heidi Pratt are also coming back for the upcoming series, reposted the same shot with the caption, "Hanging out in #TheHills."

Mischa got her big break on the 2003 FOX drama, "The O.C.," which detailed the juicy lives of a fictional group of teenagers living in a wealthy suburb of Orange County.

Now she's totally coming full circle because the premise for "The Hills," when it first aired back in 2006, was apparently inspired by her hit TV show.

Mischa confirmed that she'd signed on for the reality-ish show on Oct. 3. Other returning original cast members include Brody Jenner, Whitney Port, Jason Wahler, Justin Bobby and Frankie Delgado.

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"The Hills" reboot is expected to premiere on MTV sometime in 2019.