Mischa Barton Undergoes 'Comeback Makeover' After Joining 'The Hills' Reboot

Mischa Barton is preparing a "comeback makeover," RadarOnline.com has exclusively learned.

The former The O.C. star, 32, recently joined the cast of the reboot of MTV's The Hills. The show is set to premiere in 2019.

Now, a source has told RadarOnline.com that she's pulling out all stops to be ready for her close-up!

"Getting The Hills gig has been a lifeline for Mischa and she’s convinced that this is her one major chance to get back on top," the insider said.

"Mischa wants to look better than ever and she’s sparing no expense to make that happen."

According to the source, Barton has hired a personal trainer, nutritionist and stylist "and is trying all kinds of potions and lotions as well as laser facials to keep her looking young and sexy.

"She’s also working out every day and eating a low-carb diet."

On the new The Hills, Barton will star with most of the original cast, as well as their children, friends and some new faces.

Her co-stars will include Heidi and Spencer Pratt, Brody Jenner, Audrina Patridge, Whitney Port, Jason Wahler, Stephanie Pratt, Justin Bobby and Frankie Delgado.

Barton shot to fame at age 17 on Fox's series The O.C., which premiered in 2003. But when the show ended in 2007, her life spiraled out of control.

RadarOnline.com readers know Barton's history of legal and mental breakdowns.

Last year, she was rushed to the hospital for a mental evaluation after allegedly talking about her estranged mother and making "incoherent statements" in her backyard. She blamed the meltdown on being drugged with the date rape substance GHB.

Also in 2017, she took her ex beau Jon Zacharias to court to stop him from leaking their sex tape.

And recently, RadarOnline.com revealed that Barton is over $52,000 in tax debt.

Her post-O.C. career didn't go anywhere, and in 2016, she made a disastrous appearance on Dancing with the Stars.

But now, Barton is giving reality TV a try again—and making sure she looks new and improved, the source said.

"Mischa was the Hollywood It girl back during her The O.C. days and she’s determined to recapture some of that glory," the insider revealed.