The former King of Queens star, who joined the church with her mother at the age of 10, famously walked away from Scientology in 2013 after criticising officials' treatment of their followers.

She subsequently become a target of the organisation and its members, but Leah is using her own experiences to help others who have also cut ties with the church.

One of the people who have benefited from her support is Ron Miscavige, Scientology leader David's dad, and Leah reveals she "tracked him down" and welcomed him into her family home after he quit the faith.

"I called him and I offered my support because I know he must have felt alone," she told America's ABC News. "I just wanted him to know that we were willing to take them in. There is no place for them to go unless they have family outside of the church, which is very rare."

Leah also claims to be instrumental in convincing Ron to document his life as a longtime Scientologist and his decision to break away in a memoir, just like she did.

"(He) has a right to tell his story," the actress explained, before directing a comment at Scientology leaders: "We're all (former members) gonna speak up. You're not gonna just bully people telling their stories."

Ron's book, Ruthless: Scientology, My Son David Miscavige, and Me, is set for release next week (03May16). The autobiography has already been dismissed as "literary forgery" by Scientology leaders' attorney, Monique Yingling, who also accuses Ron of "trying to make a buck" off his son David's name.