Top celebrity addiction expert DR. Drew Pinsky agreed to keep actress Mackenzie Phillips' incest revelations a secret after she opened up to him about her relationship with her father JOHN during a televised session.
Phillips has revealed all about her perverse decade-long love affair with the Mamas & The Papas founder in a new memoir, and spoke out about the incest on U.S. TV show Oprah on Wednesday (23Sep09) - but Pinsky knew all about it months ago.
He explains the topic of Phillips' incestuous relationship with her father came up while shooting the upcoming season of VH1 reality show Celebrity Rehab.
Pinsky tells news show Extra he and Phillips talked about the relationship in private, but, out of respect for her family, she told him she didn't want those discussions televised.
But now the sick romance is out in the open, Pinsky reveals, "(John Phillips was) almost a cult leader, where he was sort of using mind control over people and telling them that his way of seeing things was the right way.
"When you're a kid, you have no other way of seeing things and if you're then given drugs and addicted at the same time, it's hopeless for the young person.
"This was despicable situation."
Phillips told Oprah host Oprah Winfrey her first sexual encounter with her father took place on the night before her wedding to Jeff Sessler in 1979, and was not consensual.
The incestuous relationship ended 10 years later after Phillips fell pregnant and aborted the child she feared was her father's.
The new season of Celebrity Rehab with Dr. Drew, which features MACkenzie Phillips, will air in early 2010.
Take a look back at October's inaugural event.
The film is expected to continue without Mendes' involvement.