Today on “Oprah,” actress Mackenzie Phillips is going to publicly speak out about her drug use and incestuous relationship with her father, Mamas and the Papas founder John Phillips. Holy cow.

The first time she remembers having sex with her father was on the eve of her wedding to Jeff Sessler. She was 19 years old. Her father showed up to stop the

wedding, got her high and she woke up from a blackout to find herself having sex with him. It continued in a haze of drugs and consensual sex, with John even suggesting they find a country where incest isn’t considered taboo.

Phillips was a star of 70s sitcom “One Day at a Time” with Bonnie Franklin, Valerie Bertinelli and Pat Harrington. She was eventually fired from the show when she couldn’t stay clean and sober. Her new book, “High on Arrival,” details her long-time relationship with her father, her struggle with drugs and her fling with Mick Jagger.

Phillips is the daughter of John Phillips and Susan Adams, half-sister of actress Bijou Phillips and singer Chynna Phillips of Wilson Phillips.