Dr. Drew Pinsky tells "Extra" the topic of Mackenzie Phillips' incestuous relationship with her father came up while shooting the upcoming season of VH1's "Celebrity Rehab." The addiction specialist breaks down the relationship between the 1960s rock star and his troubled daughter.
Pinsky says 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.
