MacKenzie Phillips has entered rehab, her attorney Blair Berk confirmed Wednesday.
Phillips is seeking treatment following her arrest on Aug. 27
for alleged drug possession at Los Angeles International Airport. She was found "carrying what appeared to be heroin and cocaine in baggies and balloons," airport police said.
Since then, the former One Day at a Time
star has been formally charged with two felonies, for possession of heroin and cocaine, as well as a misdemeanor charge of unauthorized possession of a hypodermic needle or syringe.
If convicted of all charges, Phillips faces three years and eight months in prison for the two felonies, and six months in jail for the misdemeanor, prosecutors said. Phillips's arraignment is set for Oct. 3.
The actress, 48, has long struggled with drug addiction – making multiple trips to rehab – stemming back to her youth while starring on the '70s sitcom.
1981: Phillips and her dad kick their $1 million drug habit
1980: MacKenzie's first PEOPLE cover RELATED GALLERY:
See other stars who've battled addictions