Mackenzie Phillips says ‘morals clause’ led to abrupt exit from ‘One Day at a Time’

Mackenzie Phillips is reflecting on the moment that ended her run on “One Day at a Time.”

The sitcom star recently attended Fanboy Expo Knoxville in Tennessee, where she spoke about the “morals clause” in her contract and how it contributed to her abrupt departure from the series.

“One Day at a Time” made Phillips a household name alongside co-stars Bonnie Franklin and Valerie Bertinelli. Behind the scenes, however, the actress was battling addiction. The 66-year-old said her struggles with substance abuse led to additional provisions in her contract.

MACKENZIE PHILLIPS SAYS SHE AND VALERIE BERTINELLI DRANK WINE, DID COCAINE DURING SITCOM BREAKS

Mackenzie Phillips starred as Julie Cooper on the CBS television comedy series “One Day at a Time.” She recently told a panel at Fanboy Expo Knoxville in Tennessee that she had a “morals clause” in her contract before her abrupt end. (CBS/Getty Images)

“We all had a morals contract, but mine was a little more specific,” she said at the event, People magazine reported.

According to the outlet, the actress said that if producers suspected she was “under the influence,” they would “have the right to take [me] to a doctor for urinalysis.”

Mackenzie Phillips’s character was written off after she was fired. (CBS/Getty Images)

Phillips said everything changed during a lunch break between scenes.

WATCH: MACKENZIE PHILLIPS REVEALS WILD COCAINE-FILLED BREAKS WITH VALERIE BERTINELLI

“One day, I was asleep on the couch,” she recalled. “It was lunch hour. Everybody would just take a little nap. And [co-executive producer] Patricia Fass Palmer, who I hated for years, and now we’re very good friends, she came up to me, and she said, ‘Mac, wake up. Wake up. We’re gonna take you to the doctor and have you pee in a cup.'”

Carly Simon, James Taylor, Mackenzie Phillips and Peter Asher attend a party at Studio 54 in New York City on April 17, 1978. (John Bright/WWD/Penske Media via Getty Images)

Phillips told the panel her first reaction was to ask for more time, knowing that “cocaine runs through your system so quickly.” Palmer, however, immediately shut down the idea.

Palmer then told her it was time to leave.

The cast from “One Day at a Time,” from left to right: Mackenzie Phillips as Julie Cooper, Bonnie Franklin as Ann Romano Royer and Valerie Bertinelli as Barbara Cooper. (CBS via Getty Images)

“She said, ‘No, we’re not waiting until tomorrow,'” Phillips said. “And I said, ‘OK, well.’ She said, ‘All right, Mac. Grab your stuff and get it together. Get all your stuff. And leave.’ So that’s what I did. And that was that.”

Mackenzie Phillips left “One Day at a Time” for good in 1983. (CBS/Getty Images)

Phillips starred in “One Day at a Time” from 1975 to 1980 before her character was written off following her firing, according to People. She later returned for a guest arc before leaving the series for good in 1983, the outlet reported.

Phillips has continued to speak candidly about her struggles with addiction in recent interviews.

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Mackenzie Phillips attends The Paley Honors: A Special Tribute to Television’s Comedy Legends at the Beverly Wilshire Four Seasons Hotel in Beverly Hills, on Nov. 21, 2019. (David Livingston/Getty Images)

Back in May, Phillips told Fox News Digital that one memory from her time on the show might still surprise fans today.

“Oh, I don’t know. Oh, OK. So, this might surprise you — during lunch break, Valerie and I would drive to my house, get in the pool, drink wine and snort coke,” Phillips said.

Phillips quickly clarified that Bertinelli has also spoken openly about that period.

MacKenzie Phillips and Valerie Bertinelli star as Julie and Barbara Cooper in the CBS series “One Day at a Time,” which aired from 1975 to 1984 and followed Ann Romano and her daughters moving back to Indianapolis after a divorce. (CBS/Getty Images)

“Valerie talks about it openly, so it’s not like I’m pulling her covers or anything,” she said. “… Valerie didn’t have the kind of addiction that I had; she didn’t have addiction.”

The former child star said drug use was also common behind the scenes of the sitcom.

“And you know, so we would do coke together in the dressing room and stuff,” Phillips said.

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In this undated photo, Mackenzie Philips and Valerie Bertinelli present at an event. (M. Phillips/WireImage)

“I just happened to be the one that got caught. And thank God I got caught, you know?”

Asked by Fox News Digital what keeps her grounded today, Phillips pointed to her faith and perspective.

“What keeps me grounded is my faith and just knowing how strong and … empowered my history has made me,” Phillips said.

Mackenzie Phillips attends the “Love Boat” cast christening of the Regal Princess cruise ship at Port Everglades in Fort Lauderdale, Florida, on Nov. 5, 2014. (Gustavo Caballero/Getty Images)

She said people sometimes respond to her life story with pity, but that’s not how she sees it.

“Someone was just saying, ‘Oh my God, I feel so sorry for everything you went through,'” Phillips recalled. “And I was like, ‘Don’t feel sorry for me because everything I went through, even though it was horrible and difficult, made me the woman I am today.'”

WATCH: MACKENZIE PHILLIPS SAYS FAITH AND RESILIENCE HELPED SHAPE WHO SHE IS TODAY

Phillips said she does not believe she could erase parts of her past and remain the same person.

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Actress Mackenzie Phillips signs copies of her new book, “Hopeful Healing: Essays on Managing Recovery and Surviving Addiction,” at Barnes & Noble at The Grove in Los Angeles on Feb. 28, 2017. (Paul Archuleta/Getty Images)

“If I could go back and just take this part out, then I might not be who I am,” she said. “And I feel very blessed in my life.”

The actress has been candid for years about addiction, trauma and recovery. Phillips is the daughter of John Phillips, co-founder of The Mamas & the Papas, and his first wife, Susan Adams. She chronicled her life in her memoir “High on Arrival” and later explored recovery in “Hopeful Healing.”

Actress Mackenzie Phillips and executive producer Norman Lear arrive at the premiere of Netflix’s “One Day at a Time” at The London West Hollywood at Beverly Hills in West Hollywood, on Dec. 14, 2016. (Amanda Edwards/WireImage)

During her conversation with Fox News Digital, Phillips said resilience has become central to how she views her life.

Mackenzie Phillips and her son Shane Barakan attend the opening night of “Annie” to benefit CASA of Los Angeles at the Pantages Theatre in Hollywood. (Gregg DeGuire/WireImage)

“I have a high, high resilience,” she said. “You know, the love of my son, my family, my sisters — even though that relationship was very difficult for a long time — I just believe … I have a strong faith, and, I mean, I had no choice. Be resilient or die.”

Phillips has also used her recovery to help others. In addition to acting, she has worked in the addiction and recovery field, including as a counselor and manager at Breathe Life Healing Centers.

Fox News Digital’s Danielle Minnetian contributed to this report.