First Look at Leah Remini Exclusive: 'Being Critical of Tom Cruise Is Being Critical of Scientology Itself'

— -- Actress Leah Remini reveals in an exclusive interview with ABC News ”20/20” how Tom Cruise was one of the factors that led her to break from the Church of Scientology.

“Being critical of Tom Cruise is being critical of Scientology itself… you are evil,” Remini told ABC’s Dan Harris in a new promotional clip from the interview.

Remini, 45, describes how she and her family joined the Church when she was a young girl, built a successful acting career in Hollywood while being a diligent Scientologist, and how she eventually decided to sever ties with the Church.

“As time goes on, you start to lose touch with the real world. The mindset becomes ‘Us against them,’” Remini said. “The decision to leave is you are giving up everything you have ever known and everything you have worked for your whole life.”

The actress also details her 30-year association with the Church in her new memoir, “Troublemaker: Surviving Hollywood and Scientology.”

“I feel that people need to understand this has been my whole life,” Remini said “I want them to understand how it happens.”

Watch the exclusive ABC News interview with Leah Remini on “20/20,” Friday, Oct. 30 at 10 p.m. ET.