Isabella Cruise reveals she was "drowning in problems" before she took on a role as an auditor for the controversial religion, which counts her dad as a leading member.
In an email published on Scientology blog The Underground Bunker, the 26-year-old reveals the church was "exactly what I needed".
"I dragged out the testing and correction, just made it through the drilling and then finally began my auditing adventure, and wow, I wasn't prepared," she wrote. "This IS what I had been searching for. The missing piece."
Now she's a bona-fide auditor, Isabella, who lives in London with her husband Max Parker, guides other Scientology hopefuls through the process of becoming officials at the church, warning wannabes shouldn't expect just to walk in.
"It's a few melt downs and running to the bathroom to have a mini episode, but it is worth everything because you will get through," she advised. "This is a gift to yourself and so many others.
"It doesn't matter if you aren't going to be an auditor or aren't going to join staff. If you are going to make it as a being for the long run you NEED this. That's the truth... So stop messing around and get going."
The church's auditing process has often come under fire from former Scientologists, like Paul Haggis and Leah Remini, who has developed a popular docu-series about her time as a Scientologist.
Meanwhile, Isabella's mum, Nicole Kidman, who was never a member of the church, has revealed she is supportive of her children's decisions to follow their dad into the church.
The actress has been private about her relationship with her kids over the years, but in a recent interview with Australia's Who magazine she insisted she has nothing but love for them.
"They are adults," she explained. "They are able to make their own decisions. They have made choices to be Scientologists and, as a mother, it's my job to love them. I am an example of that tolerance and that's what I believe - that no matter what your child does, the child has love and the child has to know there is available love and I'm open here."