The star, who rose to fame in shows such as Saved By The Bell and is best known for The King Of Queens series, is a former member of the church who joined as a child, but has since become one of its most prominent public opponents.

The 53-year-old claims she has been the victim of "intentional malicious and fraudulent rumours via hundreds of Scientology-controlled and co-ordinated social media accounts that exist solely to intimidate and spread misinformation", according to a lawsuit filed at Los Angeles Superior Court, reported by Sky News' US partner network NBC News.

Remini, who left the movement in 2013, co-created and hosted an anti-Scientology documentary series, Leah Remini: Scientology And The Aftermath, which aired from 2016 to 2019 and won two Emmy awards.

She is suing the church and leader David Miscavige, saying she does not believe she is the religion's first alleged victim, "but I intend to be the last".

"For 17 years, Scientology and David Miscavige have subjected me to what I believe to be psychological torture, defamation, surveillance, harassment, and intimidation, significantly impacting my life and career," the star said in a statement.

Sky News' US partner network NBC News has contacted the church and a representative for Miscavige, but they have not immediately responded to a request for comment.

Remini claims in her lawsuit that Miscavige and other defendants began attacks on her more than 10 years ago.

She alleges that current and former Scientologists were enlisted to record defamatory video statements against her - including that she "was abusive to her mother and daughter, and that she is a racist", the lawsuit says.

'Final objective of silencing me has not been achieved'

Remini said she feared for her safety and was forced to hire bodyguards for the first time in 2015, after learning private investigators allegedly working for the church were following her during the promotion of her book, Troublemaker: Surviving Hollywood, in New York.

In 2018, the church organised a meeting with celebrity Scientologists and drilled attendees on "how to attack Ms Remini's credibility, based on lies, using talking points that Scientology wrote", according to the star's lawsuit.

Remini has also accused the church of enlisting a man with "a history of mental illness and a violent criminal record" to watch her at her home in Los Angeles in 2020, the lawsuit claims. It also says her family and friends have been subjected to the harassment.

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She is seeking damages "for the enormous economic and psychological harm" that the church's alleged attacks have caused, and says she hopes to deter the church from "continuing their unlawful campaign of harassment and intimidation".

"While advocating for victims of Scientology has significantly impacted my life and career, Scientology's final objective of silencing me has not been achieved," the actress said.