Look back: 25 great 'Oprah' moments
Here's a look back at some of Oprah Winfrey's most memorable moments on television.
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Mackenzie Phillips talks about incestuous relationship (2009)( Chris Pizello / Associated Press; Angela Weiss / Getty Images )
Former "One Day at a Time" actress Mackenzie Phillips shocked national audiences in September 2009 when she revealed to Oprah that she had a decade-long sexual relationship with her father John Phillips. The actress, who was promoting her tell-all book "High on Arrival," returned for a second satellite appearance on the show later that week with half-sister Chynna Phillips. Mackenzie also revealed that it was her father, the beloved Mamas and Papas singer, who first gave her intravenous drugs.
Winfrey read comments on the show made by Michelle Phillips, John Phillips' former wife and a member of the Mamas and the Papas, that denied her claims about the relationship, but Mackenzie stood her ground with Oprah.
"When Michelle found out I was writing the book, she vowed to do everything she could to discredit me.... She's either protecting the Mamas and Papas brand or is having a textbook reaction: She's embarrassed, sweep it under the carpet, protect the abuser," Phillips told Winfrey.