Former child star Mackenzie Phillips will be a guest on Oprah today to talk about her new autobiography “High On Arrival” — and specifically, about her incestuous relationship with her own father. Feel free to stop and shudder with revulsion right there. Star Magazine says

She writes that she was 19 when her dad John Phillips — from the ’60s band Mamas and the Papas — slept with her on the night before she was to marry Jeff Sessler.

“On the eve of my wedding, my father showed up, determined to stop it,” writes Mackenzie, who was already a heavy drug user. “I had tons of pills, and Dad had tons of everything too. Eventually I passed out on his bed… I woke up that night from a blackout to find myself having sex with my own father. Had this happened before? I don’t know. All I can say is it was the first time I was aware of it.”

Their sexual relationship continued, she reveals in the book. She traveled with him and his new band, they did drugs together went to rehab together and — shockingly — even talked about running away together.

“One night Dad said, ‘We could just run away to a country where no one would look down on us,” she writes. “There are countries were this is an accepted practice.”

Jesus, there’s no reason to leave the country just to have sex with your child. Just buy a double-wide and move to West Virginia. Done and done. You don’t even have to burn any air miles!

Dita von Teese promoting her new Wonderbra because it’s not incest: