Actress Leah Remini, best known for her role in the sitcom King of Queens, has become the latest high-profile personality to quit the Church of Scientology, after more than 30 years of membership.

Remini, 43, joined the controversial religion with her mother in the 1970s, and had long been one of its most high-profile and outspoken defenders. On Thursday, however, the New York Post reported that Remini had been driven from the Church by the domineering behaviour of its leader, David Miscavige. The Post quoted an unnamed source as saying: “It all began when Leah questioned the validity of excommunication of people. She is stepping back from a regime she thinks is corrupt. She thinks no religion should tear apart a family or abuse someone under the umbrella of ‘religion’.”

Remini later issued a statement, apparently confirming her exit, in which she said: “I wish to share my sincere and heartfelt appreciation for the overwhelming positive response I have received from the media, my colleagues, and fans from around the world. I am truly grateful and thankful for all your support.” The Post’s source added that the move came as a result of “years of interrogations” and attempted “thought modification”.

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In recent months, Remini had reportedly tweeted about a change in spiritual direction, including a reference to praying as a Catholic. Her doubts about Scientology are said to have begun several years ago, however, during a dinner to celebrate the wedding of Scientology stalwart Tom Cruise to Katie Holmes in November 2006.

According to a blog by Mike Rinder, a former chief spokesman for the Church who is now one of its leading critics, Miscavige implemented “heavy-handed efforts to force [Remini] into line” after she asked why his wife, Shelly, was not at the wedding – where Miscavige was the best man. Though Remini had risen to the high church position of “Operating Thetan Level Five”, she was allegedly told by another official: “You don’t have the fucking rank to ask about Shelly.”

Mrs Miscavige is a member of Scientology’s elite “Sea Org”, who are largely secluded at secretive headquarters in Los Angeles and Florida. One anti-Church website, The Underground Bunker, claims she has not been seen in public since 2007. Other excommunicated Sea Org members have spoken of being forcibly separated from friends and family members by the Church.

Besides playing Carrie Heffernan in King of Queens, Remini has appeared in Friends, Cheers and the movie, Old School. In the past she has spoken publicly about being a member of the Church of Scientology, which was founded in 1954 by the science fiction writer L Ron Hubbard, and boasts celebrity members including Cruise, John Travolta and Cheers actress Kirstie Alley. In a April 2001 interview with CNN, Remini said she ”finds solace in her steadfast practice of Scientology”, and defended the religion, saying: “If somebody is going to get turned off about something because of what they read or heard, then that person’s not smart enough to even enter a church.”

Other high-profile Church apostates include the film director Paul Haggis, who severed ties with Scientology in 2009 over its implicit opposition to gay marriage. Rinder claimed Remini, whose restaurateur husband Angelo Pagan is also a Scientologist, “remains convinced of the value of L Ron Hubbard’s work, but will no longer tolerate the squirreling and human rights abuses perpetrated in the church”. Her representatives would not comment directly on the New York Post article.

A spokesperson for the Church of Scientology issued a statement saying they “respect the privacy of parishioners” and would not comment on individuals.