According to the church's own website, famed actor John Travolta became a Scientologist in 1975, after he was given L. Ron Hubbard's "Dianetics" while filming the movie "The Devil's Rain" in Mexico.
The church has quoted the actor as saying, "As a Scientologist, I have the technology to handle life's problems and I have used this to help others in life as well. I would say that Scientology put me into the big time."
Today, Tom Cruise is reported to be one of the top level members of the Church of Scientology, but he was first introduced to the religion by his first wife, Mimi Rogers, in 1990.
The actor has become the most recognizable face of the organization and has said that he overcame dyslexia though its teaching.
Cruise remained relatively quiet about his religious beliefs until he began openly criticizing psychiatry in 2004 and lashed out at Brooke Shields for taking the drug Paxil to deal with her postpartum depression in 2004. When the actor suddenly became the posterboy for the group, he also dumped his publicist of 14 years, Pat Kingsley, and hired his sister, a fellow Scientologist.
In 2008, the church produced a promotional video featuring a lengthy interview with the actor, discussing what being a Scientologist meant to him.
Actress Kirstie Alley was raised Methodist, but is now a practicing member of the Church of Scientology.
The church's website quotes the actress as saying, "To tell you the honest-to-God truth: without Scientology, I would be dead. So, I can personally highly recommend it."
Actor and DJ Danny Masterson was raised as a Scientologist, and is quoted on the church's website, saying:
"I have to say that one of the most important things Scientology has given me is the ability to keep my integrity together. I understand how people can get into unethical situations, and Scientology has always helped me keep my head clear and be in present time. I have been able to see situations for what they are."
Actor Giovanni Ribisi (and his sister Marissa, who is married to fellow Scientologist Beck) were raised as Scientologists.
He's quoted on the church's website as saying:
"There is a certain aspect of Scientology that helped me stay on my own path in creating life as a new game."
Actress Kelly Preston married fellow Scientologist John Travolta in 1991 and today, they're viewed as one of the organization's power couples and biggest champions.
The church's website quotes the actress as saying, "There is a way to handle every part of life with Scientology, and a way to exist that is far beyond any dream that you could ever dream. All of my dreams keep becoming realities and that's very exciting!"
Actress Juliette Lewis became a Scientologist in the 1990s and credits the church's rehab program Narconon with helping her get clean.
She's quoted on its website as saying:
"I am no longer stuck in the bottomless pit of despair and apathy. Having achieved the state of Clear is the single most important thing that I've done for myself. It has allowed me to experience life in a way I only imagined."
Nancy Cartwright is the woman behind Bart Simpson's voice, and she follows the Scientologist practices.
She's quoted by the church as saying:
"Before Scientology I had one dream of making a living, doing voice-overs for animation. After I became a Scientologist my abilities expanded so far and above what I originally dreamed for myself that I've amazed even myself at my enormous increase of abilities."
Actor Christopher Masterson was raised as a Scientologist along with his brother, actor Danny Masterson.
When the Masterson brothers opened a restaurant in Hollywood, USA Today wrote, "Danny and Chris credit Scientology with helping develop their business and communication skills."
In 2009, it was reported that Peaches Geldof started taking an interest in Scientology.
"I've been [a Scientologist] for a while now," she told the Daily Mail. "'It's like, I was confused about what path to go through and I feel like I needed a spiritual path.I felt I was lacking something when I didn't have a faith. In the end, all it's about is making yourself a better person."
Actor Jason Lee is a Scientologist and obsessed with the religion -- according to his ex-wife Carmen Llywelyn -- who in 2010 blamed the end of their marriage on his alleged obsession.
Sonny Bono was raised Catholic, but later began taking Scientology classes, as did his wife Mary Bono.
The Daily Beast reported that Bono once said, "I openly studied Scientology … and then said thank you and left … the Scientology—there was no cult thing there.”
At one time "Arrested Development" actor Jeffrey Tambor took Scientology courses, but took the time to dispel reports he belonged to the church.
"I took some Scientology classes at one time, studied Scientology for a while, but no more. I have nothing against it, but I am no longer a Scientologist," he said in 2007.
Musician Beck Hansen was raised as a Scientologist and married actress Marissa Ribisi, who is also a member of the church.
In 2005, the singer defended the organization's beliefs and practices, telling reporters:
"There's whole aspects (of Scientology) that you probably don't see. They have the success rate of getting hardcore addicts off drugs, 90-something percent maybe.
If it's something that helps you in your life it's a positive thing, so all I have to say is that you can't really make a judgement on something unless you know something about it first-hand."
TV news personality Greta Van Susteren is a Scientologist.
In 1998, The St. Petersburg Times reported that Susteren and her husband donated $100,000 or more to the church, and in a 1995 People article she said, "I am a strong advocate of their ethics.
Actress Laura Prepon began dating her "That '70s Show" co-star's brother, Christopher Masterson and converted to Scientology.
When asked by Women's Health if it was hard being a Scientologist because of so much controversy that surrounds the religion, she said:
"Anyone who knows me is just like, "Wow, if Laura is a Scientologist, then there has to be something to this." When I hear something negative, I don't get defensive. I know what's true for me and what works for me.
"Mad Men" star Elisabeth Moss is a Scientologist but has spoken out about she isn't OK with the church's rampant homophobia.
"One of the most important things I take from my church is the idea of personal freedom and our rights as human beings, and that includes the right to date a man or a woman. Personal freedom is a very important concept in my religion, and I translate that to sexual orientation. If we're all supposed to have the right to the life that we want to lead, then that should apply to the gay community. There isn't really any dogma or scripture, yes or no, right or wrong on that particular subject in my church. It's more open to personal interpretation, and that's my interpretation," she told The Advocate in March 2012.
Actress Jenna Elfman was raised Catholic, but was introduced to Scientology by her now-husband Bodhi and joined the church after they married in 1995.
The church's website quotes Elfman as saying:
"In other philosophies, my questions would get answered to some degree, but then I would have a follow-up question and there would be no answer. The logic would dead-end. In Scientology you can find answers for anything you could ever think to ask. These are not pushed off on you as, 'This is the answer, you have to believe in it.' In Scientology you discover for yourself what is true for you."
Actress Erika Christensen was raised as a Scientologist and was home-schooled by her parents before attending Delphi Academy, a private school that uses the Study Tech educational methodology created by L. Ron Hubbard.
The actress has been open about her belief in Scientology and credits it with her success. In 2004 she told the New York Daily News:
"Scientology helps me in acting to focus on communication. You can also develop and awareness of yourself."
Actress Catherine Bell was raised Catholic, but is now a Scientologist.
In 2006 she took part in a Scientology music video called "United," which promoted human rights with a rap song, and also featured Isaac Hayes, Erika Christensen, Jenna Elfman, and Lynsey Bartilson.
Actress Lynsey Bartilson was raised a Scientologist and writes on her own website:
"Ever since I was old enough to read and write I've been a fully practicing Scientologist. I'm an actress, so I always need to be totally alive and communicating. It's a wonderful feeling to know that I naturally have both of these with me always."
Actress Bijou Phillips is the daughter of John Phillips of the Mamas & the Papas, and married to fellow Scientologist Danny Masterson.
In 2009, the actress went on a bit of a rant in an interview with Paper magazine, defending the religion's belief in shunning psychiatry:
"My grandparents didn't take any pills, and they were fine. Just buck up and get over it. Stop being such a f--king pansy," she said.
Actress and talk-show host Leah Remini was a big proponent of the Church of Scientology.
She was quoted on the church's website, saying: "Scientology has been my road out. There is nothing about my life that I feel apathetic or unhappy about. Scientology gives you hope and the certainty that you can improve any condition. This, to me, is priceless."
UPDATE: Remini reportedly quit Scientology in July 2013, after being subjected to "years of 'interrogations' and 'thought modifications.'"
Lisa Marie Presley, former wife of Michael Jackson and only daughter of Elvis, was a Scientlogist like her mother Pricilla Presley.
In the past, there have been reports Lisa Marie had become disillusioned with the church and cut ties with it, but the organization's website still lists her as one of their biggest successes.
UPDATE: Presley has indeed left the church of Scientology and told USA Today "I got bad advice. I was insulated with no grip on reality. They were taking my soul, my money, my everything."