Mackenzie Phillips Back on Oprah

Mackenzie Phillips, the actress famous for her 70's show "One Day at a Time" shocked and "ewwed" many of us when she reveal that she had had an incestuous relationship with her famous singing father, John Phillips, of the Mamas and the Papas.

Phillips said that her father raped her the night before she was to get married, then carried on an affair with her for about ten years after.

Mackenzie's stepmothers refute the claim that John, although famously addicted to drugs and alcohol, could ever do that to his own child.

Mackenzie is returning to Oprah today to speak more about her life, spurred on by the release of her memoirs "High on Arrival".

Half-sister, Chynna Phillips, from the singing group Wilson-Phillips will be speaking out for Mackenzie, although it is not clear in what capacity. She is not denying her father may have done these acts, but is having a hard time believing it.

"High on Arrival" has caused a stir within the Phillips family, as well as the nation.