Content warning: this article discusses abuse and incest. 

Mackenzie Phillips is speaking on a painful period from her past.

The One Day at a Time actress recently discussed the decade-long incestuous relationship she had with her father, musician John Phillips—and why she's chosen forgiveness.  

"Dad was something else," Mackenzie said during a sit-down with her sister Chynna Phillips Baldwin. "And I get a lot of criticism, and a lot of trolling online, for having forgiveness in my heart. Forgiveness, because forgiving is for me, not for the other person. And forgiving doesn't mean I cosign or agree with what I'm forgiving him for."

Mackenzie—who has previously opened up about her relationship with the Mamas & the Papas singer in her 2009 memoir—said the relationship began when she was 19 when her father raped her. Their relationship lasted for 10 years, coming to an end after she became pregnant and wasn't sure if her dad was the baby's father.

"It's very, very complicated," she told Chynna in a video shared to YouTube Nov, 29. "And yet, I am at peace."

Their late father, agreed the sisters—Mackenzie's mom is Susan Adams while Chynna's is Michelle Phillips—was a complex figure.  

"So many different levels to who he was," Chynna said of John, who died in 2001. "Obviously he's an amazing songwriter and, you know I loved his laugh, and yet there was this whole other side to Dad that was, I mean, kind of, like a monster."

To which Mackenzie, 64, added, "Very, very dark, dark side."

Chynna echoed what her older sister said. "He was so dark, and you just didn't know who you were going to get," the 55-year-old added. "It was very unpredictable."

Though Mackenzie—who is now sober—revealed she lost relationships with much of her family after coming forward about the relationship, Chynna stayed by her side.

"I want you to know," Chynna said to Mackenzie, "that when I stood by you, I meant it with all my heart, I really did. And I believed you and I want you to know that I was proud of you for coming out even though it was painful for everybody."

Back in 2009, after the release of her memoir, Mackenzie got candid about this part of her life during an interview with Oprah Winfrey.

"I was a little girl who had this larger than life [father]," she said at the time. "I adored my father, I waited for him over and over again. I was constantly trying to get his attention, and had this deep, visceral yearning for connection."

A yearning that, she added, got twisted when combined with the drugs and alcohol she used at the time.

"Over time," the mom of 35-year-old son Shane (with guitarist Shane Fontayne) explained, "your perception of things as they should be, the world as it is, the rules of society, becomes warped and twisted."

"Of course I was old enough to know better, and clearly from the way I talk about it in the book I knew better," she continued. " I can't explain this away. It happened."

But it finally stopped when she became pregnant. "The implications, the reality of that, I had an abortion" she said. "And I never let him touch be again."