Mackenzie Phillips was raped as a teenager - several years before she embarked on an incestuous relationship with her father JOHN.
The former child star stunned fans and family by detailing in her new tell-all book High on Arrival how her father raped her the night before she married Jeff Sessler in 1979.
Now she reveals it wasn't the first time she had been assaulted - a motorist sexually abused her at the age of 14 as she hitchhiked in Hollywood.
Speaking to U.S. chat show host Larry King, Phillips says, "I was 14... I was hanging out with some friends at a club on Sunset (Boulevard) called Rodney Bingenheimer's English Disco. And I was allowed to hitchhike at that age... And we were hitchhiking home, my friends, Billy, Jody and I. And a gentleman. Someone I thought I knew. We thought we knew this man. We got in the car and he turned off of Sunset."
The man ordered her friends out of the car before holding a knife to Phillips' neck and speeding off.
She adds, "He took me up into the hills and raped me. And he told me he was going to kill me... I was let out of the car on the street above Sunset. He shoved me out of the car. I ran back down to the club. The police were there. Billy and Jody were there... Everyone was crying. And I was taken and done (sic) a rape kit on. I was clearly raped."
The man repsonsible for the attack has never been traced.