Credit: EM43/Splash News Online

Mischa Barton got her hair did -- and she's barely recognizable!

The volatile actress, 24, said goodbye to her long, dark locks after spending eight hours at the Byron Tracy Salon in Beverly Hills on Tuesday.

When the former star of The Beautiful Life and The OC emerged, she sported chin-length, dirty-blonde locks and dark-red lipstick.

No wonder she's looking for a new look: last year was a challenging one for Barton. She was placed under involuntary psychiatric hold at L.A.'s Cedars-Sinai Medical Center in July (she claimed it was a misunderstanding related to oral surgery), and her comeback show The Beautiful Life was cancelled within weeks of its premiere on the CW.

Barton will next appear in a guest-starring role (as a prostitute) on Law and Order: SVU.