The former child star of "One Day at a Time" returned to the Oprah Winfrey Show today to defend her decision to write her bombshell book "High on Arrival," in which she confessed to engaging in a 10-year consensual sexual relationship with her father, rock star John Phillips, the lead singer for the '60s group the Mamas and the Papas.
"It's been heartening and heartbreaking at the same time …with the way my family's reacting," she said about the response to her appearance on Wednesday.
Mackenzie, 49, spoke to Winfrey Friday by satellite. Her half sister Chynna Phillips, whose mother is actress Michelle Phillips, appeared live in Winfrey's studio. Chynna, an actress and singer who is now half of the Christian duo Chynna and Vaughn, said she wanted to appear separately so that her words would not be "convoluted."
Asked about her reaction to her sister's confession on the show, Chynna responded: "I was praying for her the whole time. It's very taboo. Many people were repulsed, horrified, for her to come out and talk about something no one wants to hear about, she had the courage. I'm proud of my sister."
When asked if she believed her older sister, Chynna laughed at first.
"How can the details be perfectly accurate, when you're on drugs?" she said.
"I do know there was a consensual relationship between my father and sister," she continued. "I've known that for about 12 years."
She described the conversation in which Mackenzie first told her about the relationship. Chynna was in an airport, when her sister, with whom she wasn't always close, called her.
"She said, 'There's something you need to know...I had this consensual relationship with dad for over 10 years,'" Chynna recalled. "You could have dropped a piano over my head and I wouldn't have felt it."
Chynna said Mackenzie told her about a month before the book was published that she was planning to go public with the relationship. Chynna said she wished that she had had more time to prepare for her sister's bombshell.
"It's 13 years later and I still haven't digested this information," she said.
Mackenzie responded: "I'm really sorry Chynna to put you in this position, but I don't regret writing the book."
Winfrey also read a letter from Mackenzie's other half sister, singer-actress Bijou Phillips. Bijou was 13 when Mackenzie first told her she had a consensual sexual relationship with their dad. But Bijou said Mackenzie denied it shortly after. She said her older sister's memories are also "clouded by 30 years of drug abuse."
Bijou also wrote that if the man who raised her as a single parent from the time she was three was capable of sexual abuse, "it's heartbreaking to think why would (my family) leave me alone with him."
A teary Mackenzie responded that she never thought her younger sister was in danger of being sexually abused, adding, "I did take her out of there at one point when I thought she wasn't being properly cared for."
Mackenzie also responded to a statement from her stepmother, Michelle Phillips, also a member of the Mamas and the Papas, who told the Hollywood Reporter on Wednesday that she believed the allegations were false.
Michelle said Mackenzie had "a lot of mental illness" and that "she's had a needle stuck up her arm for 35 years."