Isabella Cruise has thanked her Hollywood star dad Tom Cruise for helping her through her Church of Scientology training.

Isabella Cruise

Isabella Cruise

The 26 year old - who is the adopted child of high ranking Scientology member Tom and his ex-wife Nicole Kidman - has spoken out about how her training to become an auditor within the London branch of the unconventional religion was "exactly what she needed" and is the "missing piece" in her life.

An auditor is extensively trained member of the sci-fi cult who helps other members through intense self-examination sessions using an electronic device called the E-meter and encourages those being audited to share traumatic experiences either in this life or past incarnations.

In a lengthy letter posted to Tony Ortega's blog The Underground Bunker, she writes of her training: "It turned out it 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. This IS what I had been searching for. The missing piece. Suddenly everything began to make sense."

Isabella - who has a brother Connor, 23, who was also adopted by Tom and Nicole - says the course has now shown her "without a doubt" that the "tech" of Scientology works and she is committing her life to the church.

She added: "The internship, for me, is what made me a Scientologist. I don't just believe the tech works now. I know without any doubt that it does."

Scientology was created in 1952 by American science fiction author L. Ron Hubbard and is based on the belief that human beings are immortal, that a person's life experience transcends a single lifetime.

Bizarrely, Hubbard claimed that billions of extra-terrestrial beings were sent to Earth by Xenu - the dictator of the 'Galactic Confederacy', comprised of 26 stars and 76 planets including Earth - who gathered them around volcanoes and then destroyed the aliens with hydrogen bombs.

The aliens' souls attached themselves to chosen humans, known as thetans, who will be one day be saved from their life of spiritual harm.

Isabella went on to praise her dad Tom, 56, and claimed she would have "drowned in her own problems" without the help of the 'Top Gun' star.

She wrote: "Thank you to my Dad for everything ... I would have drowned in my own problems if you hadn't been there to sup [sic] me or get me through the preliminaries. It took a whole family and an org to get me here."