The Most Shocking Celebrity Sex Scandals. As Pop Eater tells it “First Mackenzie Phillips tells us she was keeping it in the family with her Mamas & the Papas papa, then it turns out David Letterman was mixing business with a whole lot of pleasure. Celebrity sex scandals have taken a weird turn this fall, and that’s saying a lot — it takes a heck of a gossip mag-scorcher to knock Joe America out of his cozy La-Z-boy.

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Michelle Phillips, the ex-wife of the late John Phillips says her stepdaughter Mackenzie Phillips is lying about having an incestuous affair with her father. So incestuous or not? Read on.. ( the blonde is the stepmother)

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more photos of Mckenzie Phillips and Michelle Phillips after the jump..

Michelle Phillips says that in 1997, Mackenzie told everyone in their extended family that she and her father, Michelle’s famous former husband, had had a sexual relationship. “ Makenzie called Michelle back and said, ‘You know I’m joking,’ ”  “I said it wasn’t funny. Mackenzie said, ‘I guess we have different senses of humor.’ ” – via Showbiz 411

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Mackenzie Phillips reveals she slept with her own father! Don’t hate my father,” Mackenzie Phillips tells People via Popeater. Phillips has a tell-all book coming out today revealing that her dad, John Phillips of the 60s band the Mamas and the Papas and her had an incestuous relationship.

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more photos of Mackenzie after the jump..

Another child actress is busted with cocaine and heroin….and it isn’t a recent star.  Mackenzie Phillips, from the hit show One Day At A Time, was picked up in LAX.

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More pictures after the jump…

The actress has a long history of drug abuse.  It was the reason why she was kicked off the show in the early 80s – she couldn’t keep clean.  Her co-star was Valerie Bertinelli, who did manage to stay clean and go on and have a better career.  Well, sort of since she married Eddie Van Halen, a notorious drug user and alcoholic.