trust, does your food go beyond? seconds. good evening. thanks for joining us. he's one of the most outspoken critics of the controversial church of scientology. having grown up in a religion that believes in intergalactic theology. tonight actress leah remini, one of scientology's highest-profile ex-members, taking on its biggest star, tom cruise. now finding herself in the crosshairs. she cat downsat down with my "nightline" coanchor dan harris. >> reporter: she was not only tv royalty starring in "the king of queens." she was scientology royalty. gracing the cover of the church's official celebrity now, however, leah remini has. >>ed from a fierce defender of the fade -- >> without any scientology organization, things are not going to change on this planet. >> reporter: to the most famous member to leave and go public with her new book called "troublemaker" about to hit shelves, the church is calling her a liar, self-absorbed, rude, and embarrassing. as leah levels scathing criticisms against scientology and its most well-known follower, tom cruise. >> i think it's a privilege to call yourself a scientologist. it's something that you have to earn. >> reporter: in fact, as you will hear tonight, leah says the beginning of the end of her more than three decades in scientology came at the tom cruise/katie holmes wedding. but leah's scientology story started, she says, when her mom vicki, fresh off a divorce, threw herself into the religion founded by science fiction writer l. ron hubbard. >> we know the basics of human existence and so forth applied in almost any sphere. >> your understanding, what is the goal and promise of scientology? >> to freeman kind. to make a sane world. >> reporter: eventually vicki decided to bring her lawyers leah and nicole in and put them on course. >> what does that mean, go on course? >> you learn how to apply the techniques of scientology. to yourself and others. >> for a kid who was always looking around, comparing herself to other people, to be part of a faith where you had a mission to save -- >> the planet. save the planet. >> that must have been a big deal. >> reporter: when leah was a teenager, her mom decided to enroll her in the sea org, the full-time religious order of the church, and to move the family to scientology's spiritual headquarters in clearwater, florida, known as the flag land base. >> they provide room and board and you work there and you sign a billion-year contract. >> billion-year contract? >> correct. >> you as a child signed this contract? >> correct. >> reporter: there it is in writing. scientologists believe in reincarnation and sea org members are expected to keep working every time they come back. that's leah and nicole in their sea org uniforms. smiles notwithstanding, she very quickly started causing problems in the sea org. >> what trouble was she getting into? >> i think mainly it was her mouth. >> reporter: sherry ellens, friend and fellow sea org member, said leah would complain about the living conditions, the food, the hard work. >> when you first get in they have you doing physical labor. kids cleaning uniform shirts. >> what work were you doing? >> it could go from working in a laundry room to working industrial sanders to -- >> industrial sanders? >> uh-huh. >> reporter: leah says things came to a head when she was brought up on ethics charges for her involvement with boys. >> i allowed my boyfriend at the time, who was like my first boyfriend, to go like this over >> that was enough to get you -- >> that was light, very light. it wasn't a real grab, dan. light. >> it's very hard to have this discussion with a straight face. >> sorry. >> reporter: the church says children are no longer admitted into the sea org but back when leah was a member the living conditions quoermed to state health codes. the church also says leah was dismissed for her inability to maintain the ethical standards relating to fraternization. they say leah petitioned to stay but failed. leah and her family say they left voluntarily. either way the family stayed in the church and soon ended up in los angeles where leah launched her acting career and says what she was learning in scientology proved extremely useful. >> how helpful was scientology in terms of getting your acting career started? >> there's tools that are very, very helpful to you in your life, to you as an actor. i walked into a room where some people might feel -- cower in front of a casting director, i wasn't. >> reporter: scientology helped and so did her own natural propensity for comedy, which we saw firsthand in our interview. >> look at me, i'm dan, very serious, look at me! >> reporter: with astonishing speed leah started landing best roles on shows such as "cheers" -- >> you're pregnant. >> that is a rude and unfair thing to say. >> i am pregnant. >> reporter: and "nypd blue." >> what led up to him standing you? >> what led up to it was we had a fight, he took a knife, he tried to murder me. >> reporter: then the call for the show that would change her career and her life. "the king of queens." >> please be nice to marie. >> i am trying. fy weren't trying she'd have a fork sticking out of her neck. >> reporter: the role of carrie hefer hefernen, the wife of everyman doug, turned out to be a sitcom match made in heaven. >> it must have been a buzz. >> it was amazing. it really was. >> reporter: her rising star also brought leah into the orbit of scientology's most famous member, tom cruise. who declined to comment for this report. >> what your impressions of him? >> at first it's very effusive, it's very loving. what are you doing, how are you doing, yeah, great, great, great, great! >> reporter: this is them hugging at a movie premiere. leah says exposure to cruise opened her eyes to his vast influence in church, exemplified by a call she got from a church official. >> tom wants you to come over and teach him salsa dancing. >> reporter: she says two high-ranking scientology his home and so was his new girlfriend, katie holmes. >> he was like forcibly kissing katie. i said, hey, get a frigging room. i was written up for that. >> reporter: that's right. she says one of those officials essentially tattled on her. leah says she continued to hang out with cruise but did not hesitate to speak up when she thought he was damaging the church in the public view, such as this infamous couch-jumping before? >> what the hell is this guy doing? we need to rein it in. we need to stop all this. and he just needs to be an actor. okay? i was immediately dealt with. >> how? >> immediately. the only reason you're saying these things is because you have your own transgressions, so you then become guilty. being credit careful tom cruise is being critical of scientology itself. you are a person who is anti the apes and goals of scientology, you are evil. >> reporter: leah says she became increasingly displayed by the fawning attention church officials heaped upon the a-lister who was extremely close with the head of scientology. despite that she says she was genuinely excited when, one day in 2006, cruise invited her to his wedding with katie holmes. a three-day, star-studded affair at this grand italian castle. and when we come back, how the cruise/holmes wedding would become a crucial turning point in leah's relationship with the church in which she was raised. >> you left the wedding on a mission to save scientology? >> right. i thought, i now see where the cracks are in our church. and it's the leader david, it's tom cruise, they were bringing scientology down.family? my li'l buddy? and what if this happened again? i was given warfarin in the hospital but i wondered if this was the right treatment for me. then my doctor told me about eliquis. eliquis treats dvt and pe blood clots and reduces the risk of them happening again. not only does eliquis treat dvt and pe blood clots, but eliquis also had significantly less major bleeding than the standard treatment. knowing eliquis had both... turned around my thinking. don't stop eliquis unless your doctor tells you to. eliquis can cause serious and in rare cases fatal bleeding. don't take eliquis if you have an artificial heart valve or abnormal bleeding. if you had a spinal injection while on eliquis call your doctor right away if you have tingling, numbness, or muscle weakness. while taking eliquis, you may bruise more easily... and it may take longer than usual for bleeding to stop. seek immediate medical care for sudden signs of bleeding, like unusual bruising. eliquis may increase your bleeding risk if you take certain medicines. tell your doctor about all planned medical or dental procedures. eliquis treats dvt & pe blood clots. plus had less major bleeding. both made switching to eliquis right for me. ask your doctor if it's right for you. innovative sonicare technology with up to 27% more brush movements versus oral b. get healthier gums in 2 weeks guaranteed. innovation and you. philips sonicare save when you buy the most loved think your heartburn pill works fast? take the zantac it challenge! zantac works in as little as 30 minutes. nexium can take 24 hours. when heartburn strikes, take zantac for faster relief than nexium or your money back. it was clearly the biggest wedding in scientology history. but it marked the beginning of the end for actress leah remini. scientology had been her spiritual home for more than 30 years until she says she found out firsthand the high cost of crossing one of scientology's most prominent members. here again is dan harris. >> reporter: the cruise/holmes wedding was an opulent, celebrity-drenched affair in italy. leah remini was captured with friends jennifer lopez and then-husband marc anthony. >> i was hoping to get a picture where i looked gorgeous and stunning. instead i look like that. >> reporter: leah says at the wedding where scientology's chairman of the board david miscavige served as best man church officials took their cruise adulation to a new level. she was annoyed by what she saw as ham-handed efforts to separate her from her friend jennifer lopez by having them travel in separate vehicles and sit at different tables. >> they were trying to distract me. >> why? >> i could only assume. because they wanted to take jennifer a scientologist, maybe i was barring that road for them. >> reporter: the church tells abc news in regards to the wedding, every claim ms. remini has made is not only untrue but ridiculous and stupid. for her part, leah says what she saw was enough for her to take a radical step. she says she filed a wide-ranging knowledge report to the church, complaining about various scientologists at the wedding. >> you left the wedding on a mission to save scientology? >> right. i thought, i now see where the cracks are in our church. and it's david miscavige, it's tom cruise. down. >> reporter: but to her dismay she says she arrived home and learned that numerous scientologists had filed reports on her. >> that i had disrupted the wedding, that i basically destroyed the wedding. >> reporter: leah showed us this document which she claims to be holmes herself. >> it starts with, i was displayed at the behavior of leah remini leading up to the events during our wedding and wedding. >> reporter: leah says she had crossed two pillars of scientologist, tom cruise and the chairman of the board david miscavige. and now she was being taken to task. >> basically they were just trying to get me to recant what i said. to apologize for ruining the wedding of the century. >> why didn't you just leave? >> i wasn't ready to leave the church. >> reporter: in fact, she says she was so loyal that before the wedding, she'd even cut ties with her old friend sherry owens, now an ex-scientologist, because leah thought sherry's brother had become antagonistic toward the church. >> did she formally disconnect from you? >> she never said anything to me. but i never heard from him. >> reporter: leah was, in some ways, living a double life. outwardly a committed scientologist. but inwardly nursing doubts. not just about the organization, but also about its cosmic theology. one example, back in 2003, when of scientology's bridge to total freedom. operating thetan 3, a point at which she says key church secrets about the history of the universe are revealed. written by l. ron hubbard he tells a story about an intergalactic warlord named zenu. >> who was xenu? >> some galactic confederation, there was a war, there was a volcano, they took the spirits of people and they encased them into something, into a volcano, blew them up then those spirits are now inside of you. on you. in you. things. >> when you read that, did you think this is true? sp when i read that, i thought >> that wasn't enough to quints you -- >> what am i doing, walking away from my mother? >> reporter: the church would not talk about its advanced scriptures but told abc news it have confidential scriptures and practices. in 2012, another major inflection point in leah's relationship with scientology. katie holmes, who leah says had written one of those knowledge reports against her, publicly left tom cruise. leah says she felt vicinity dated. >> i said, where's my apology? >> reporter: here's one. this week katie holmes wrote to haines news. she neither confirmed nor denied writing that knowledge report but said, i regret having upset leah in the past and wish her only the best in the future. >> do i get an apology from tom and david massiscavige? >> reporter: she says she decided to commit a serious infraction within scientology, she went ob linenline to see what critics were saying. she saw reports of families who say they were torn apart by the church's practice of disconnection, the shunning of ex-members by friends and relatives still in the church. >> i want this horribleractice of disconnection to end. >> reporter: she says she also saw allegations by former top officials who say they were punched or slapped by david miscavige. >> i was heartprone for myself and my family. i didn't want these things to be true. >> reporter: scientology adamantly denies it splits up families saying disconnection is voluntary. the church repeatedly denied miscavige physically struck anyone. leah says the situation came to a head when the church sent two high-ranking officials to her home, a visit that turned into an argument and according to her husband almost much more. >> one of them called her a name. >> what did he call her? >> he called her a bitch. >> reporter: leah says she was ready to leave. the church says she was actually expelled for ethical lapses and claims she tried to stay. leah denies all of that. either way there was still an enormous emotionally fraught question lingering -- would her family stand by her? known. and cut ties with my own husband, my own mother. because you don't know what they're going to decide. >> reporter: in the end, with the reminis, that is not how it went down. >> how much did it mean to you that your family stood by you? >> it means everything. >> reporter: leah reconnected owens. >> so she e-mailed me a sweet e-mail and we agreed to meet for coffee. we met and it was like no time had passed. >> reporter: things were much less cordial with the church, however. leah decided to make her exit very public. even taking her beef to the ballroom on "dancing with the stars." >> the church is looking for me to fail so they can say to their parishioners, see what happens about you leave the church? they're waiting for me to fail. >> reporter: just this week with leah guest hosting "dancing with the stars," the church is ramping up its criticism. even hand-delivering packets of information to the lobby of abc news filled with damning statements ss like this. >> let me read you this. given leah remini's insatiable desire for attention it comes as no surprise for two years she has been incapable of moving on with her life and remains obsessed with shamelessly exploiting her former religion in a pathetic attempt to get publicity publicity. >> i agree with them, i wish i quickly. >> reporter: two years out of the church, leah says her life is now better than ever. that the ordeal has reinforced the bonds within her family. >> i don't regret spending my life there. because it really did teach me a lot. and because we've all survived it. we're all surviving it and living life. it's kind of like we have a gift of a second chance at life. >> reporter: for "nightline" this is dan harris in los angeles. we'll be right back. good. very good. you see something moving off the shelves and your first thought is to investigate the company. you are type e . yes, investment opportunities can be anywhere... or not. but you know the difference. e trade's bar code scanner. shorten the distance between intuition and action. e trade opportunity is everywhere. and i quit smoking with chantix. i have smoked for thirty years and by taking chantix, i was able to quit in three months. and that was amazing. along with support, chantix (varenicline) is proven to help people quit smoking. it absolutely reduced my urge to smoke. some people had changes in behavior, thinking or mood, hostility, agitation, depressed mood and suicidal thoughts or actions while taking or after stopping chantix. some had seizures while taking chantix. call your doctor right away. tell your doctor about any history of mental health problems, which could get worse or of seizures. don't take chantix if you've had a serious allergic or skin reaction to it. if you have these, stop chantix and call your doctor right away as some can be life-threatening. tell your doctor if you have heart or blood vessel problems, or develop new or worse symptoms. get medical help right away if you have symptoms of a heart attack or stroke. decrease alcohol use while taking chantix. use caution when driving or operating machinery. most common side effect is nausea. i can't believe i did it. i quit smoking. you know, the scandals that rocked the nation from john pen 98 ramsay, o.j. simpson, kimberly mays famously switched at birth. the years may have passed but they've each left an indelible mark. where are they now? 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