Now that Mackenzie Phillips has spilled the beans about her messed up life in a new tell-all book and sit down interview with Oprah, people are responding to the shocking news that her father, John Phillips of the Mamas and the Papas, had a sexual relationship with Mackenzie.

Mackenzie Phillips reveals a 10-year affair with John Phillips in her memoir “High on Arrival,” and half-sister Chynna Phillips believes Mackenzie’s telling the truth.

Chynna Phillips recounts receiving a call from Mackenzie in 1997: “She said, ‘I don’t know why, but I just really felt the need to call you and tell you something that I think you need to know. And she went on to tell me that she had had an incestuous relationship with our dad for about 10 years.”

Chynna tells Us Weekly, “Somebody could have dropped a piano on my head and I probably wouldn’t have felt it. But I knew it was true. I mean, who in their right mind would make such a claim if it wasn’t true?”

Image from INFPhoto.com