Mackenzie Phillips and Oprah sit down for an interview to air Wednesday, September 23. Mackenzie Phillips talks with Oprah about her life growing up as daughter of John Phillips, from the band The Mamas and The Papas, and her struggles with drug addiction.

Mackenzie Phillips will be promoting her new book, “High on Arrival,” on Oprah, which hits stores September 23.

Of course, the bombshell that people will be tuning in to Oprah to hear is Mackenzie Phillips’ 31-year old family secret.