Transcript for Leah Remini: 'Being Critical of Tom Cruise Is Being Critical of Scientology Itself'
this half hour with an ABC news exclusive, former sitcom star Leah remini taking us inside the controversial church of scientology, her new book "Troublemaker: Surviving Hollywood and scientology" revealing what she says her life was like in the church and surprising claims that the church's most famous member, Tom cruise, ABC's Dan Harris is back here with more. Good morning, Dan. Reporter: Hey, robin, good morning. Never has a scientologist this famous criticized the church. Leah remini says she joined scientology at the age of 8 and rose to many so of its highest spiritual levels. Now she's giving a scathing insider account of the faith that once dominated her life. I'm going to get there first. Reporter: During her nine seasons on the hit CBS show "The king of queens," Leah remini appeared to be the ideal scientologist, famous and fiercely loyal but behind the scenes she says she harbored grave doubts including about the world's best-known scientologist, Tom cruise. I think it's a privilege to call yourself a scientologist and it's something you have to earn. Being critical of Tom cruise is being critical of scientology itself. You are a person who is anti the aims and goals of scientology. You are evil. Reporter: Leah says she first entered cruise's orbit as her own career skyrocketed. What were your impressions of him? At first its very U fusive, very loving. You get to laser in on you and you're the most important thing that ever happened. It's what are you doing? How are you doing and yeah, great, great. Great, great, great, great. Reporter: But Leah says her exposure to cruise, this is them hugging at a movie premiere opened her eyes to his vast influence within the church. An influence she says was exemplified by a call she got one fight from a church official. Tom wants you to come over and teach him salsa dancing. Reporter: When Leah and her husband Angelo a professional entertainer arrived at his home they say two high ranking scientology officials were there with Tom and his new girlfriend Katie Holmes. He was like forcibly kissing Katie, you know, I said, hey, get a frickin' room and I was written up for that. Reporter: That's right. She says one of those church officials essentiallytalitile the on her. Leah says it's a common practice, church members regularly write what are called knowledge reports on one another for breaking rules. She says the accused then have to answer the allegations in auditing sessions. Does it create an atmosphere of mistrust. You can assume if you say something that is critical to the church you will be written up, husband, wife, mother/daughter, it's what the group does to regulate itself. Reporter: Leah admits to writing knowledgeable reports herself frequently. So did you ever write up a report on your husband? Hell yeah, I wrote Angelo up all the time. Reporter: With her new book "Troublemaker" about to hit shelves the church hand delivered a pact of information to ABC news containing a series of damning claims about Leah including that she was actually expelled from scientology for ethical lapses and claims that she tried to stay. Leah insists the separation was her idea. So that is one of their main arguments you're just trying to stay relevant. Here let me read you. Please. Reporter: Given Leah remini's insatiable desire for attention it comes as no surprise for two years she's been incapable of moving on with her life and shamelessly exposing her former religion in a pathetic attempt to get publicity. Yes, I agree with them. I wish I too could get over 30 years of this quickly. Unfortunately, it's going to take some time. Reporter: And coming up tonight on "20/20," you're going to hear how Leah's family members many of whom were deep into sentology reacted to her departure from the church and you'll hear from Katie Holmes, the former wife of Tom cruise, what she is now saying about Leah guys. Leah does not hold back when she talks to you. No. It's must-see TV tonight. You can see it all at 10:00, 9:00 central on ABC.
This transcript has been automatically generated and may not be 100% accurate.