Mackenzie Phillips claims she snorted coke and drank wine with Valerie Bertinelli during One Day At A Time lunch breaks

Mackenzie Phillips is revealing some of the debauchery that she claims went on behind-the-scenes with Valerie Bertinelli on their family-friendly sitcom One Day at a Time. 

The pair played sisters Julie Cooper and Barbara Cooper on the series from 1975 to 1984, but Phillips struggled with substance abuse and was fired twice from the show. 

Now Phillips, 66, is recalling how they would unwind from the set at her home with wine and cocaine.  

'So this might surprise you that during lunch break, Valerie and I would drive to my house, get in the pool, drink wine, and snort coke,' she told Fox News Digital at the Chiller Theatre Expo in Parsippany, New Jersey. 

She added what she was sharing was nothing new and stressed she was the one struggling with addiction, not Bertinelli, 66.

'But Valerie talks about it openly, so it’s not like I’m pulling her covers or anything,' she said. 'The thing was that I was the, you know, Valerie didn’t have the kind of addiction that I had, she didn’t have addiction.'

'And you know, so we would do coke together in the dressing room and stuff,' she said. 'I just happened to be the one that got caught. And thank God I got caught, you know?'

The Daily Mail has contacted representatives for Bertinelli for comment but have not yet heard back. 

Bertinelli previously admitted she was a teenager when she first tried cocaine with Phillips, according to Today.

The drug use continued into her relationship with her ex-husband, the late Eddie Van Halen.  

'The priest we tapped to perform the ceremony gave us questionnaires so he could get to know us better and offer more personal words. As we filled out the forms at home, we each held a little vial of coke,' she recalled in her memoir, Losing It. 

'It doesn't really bode well for the marriage, I don't think,' she added.  

In 2023, Phillips described herself as the 'obvious rebel' on set, saying in an interview for her sister Chynna Phillips's YouTube channel: 'I got in trouble, I got caught doing drugs and all this kind of stuff... and I talk about it in High On Arrival, with Valerie's permission, is that what people didn't know is that we were leaving for lunch and going up to my house and drinking wine in the pool and chopping lines on the coffee table.'

Phillips clarified that Bertinelli wasn't doing drugs to the extent she was at the time and was able to 'slide under the radar.'

Phillips won her first major film role at the age of 12 in George Lucas's 1973 movie American Graffiti and went on to star in popular sitcom One Day At A Time as rebellious teen Julie Cooper.

The hit show ran from 1975 to 1984 and, according to Variety, she was the highest-paid actor on the show at the time.

However despite her massive success at such a young age, her career was brought down by drug use — as a result she was fired twice from One Day At A Time.

Phillips said her father taught her to roll joints at 10 and she tried cocaine for the first time at 11.

Her life began to spiral out of control because of her substance abuse, and she has previously spoken out about how she and her father, John, would do drugs together.

In her 2009 memoir, High On Arrival, Mackenzie alleged that she and John had a 10-year incestuous relationship, a bombshell claim that not only rocked the public — but divided her family.

During her interview with Chynna, she also reflected on when she was fired from One Day At A Time.

'My addiction was so powerful and so out of control that when I was fired for the second time from the show for drug use, I thought, "Ah screw them, you know, I'll get my next job in a minute," that did not happen. And I became basically unhirable for a long, long time,' Mackenzie said.

'Once I got sober for the first time I realized that I had to put my pride in my back pocket and not go, "Well I was on the biggest TV show all time," because there were many like me who refused to audition and I just said you know what I'm putting that behind me, and I went out and I pounded the pavement and I auditioned against a bunch of other young women and I started booking gigs and I started booking jobs.

'I was sort of in episodic hell for a long time and then the Disney Channel show [So Weird] came along... it was a great show, it was so much fun.'

She appeared in 65 episodes of So Weird from 1999 to 2001, but didn't land another major role again until Orange Is The New Black (2018) and the One Day At A Time reboot (2017-2020).

In 2008, Phillips pleaded guilty to possessing cocaine after she was arrested at Los Angeles International Airport earlier that year.

It was alleged she was carrying drugs packaged in balloons and plastic bags, Reuters reported.

As part of her plea, Phillips agreed to complete an 18-month drug treatment program, according to Fox News.

Now Phillips has turned her life around and uses her own past struggles to help those battling addiction.  

Mackenzie has since become an addiction counselor at the LA treatment facility Breathe Life Healing Centers.

'My addiction was so powerful, and so rooted in early trauma, that I lost myself for many years. Now, with a strong recovery I’m committed to helping others find their voice at Breathe Life Healing Centers,' she says on their website.