Tom Cruise will save the world from aliens — not on the big screen but in real life.

His day job as an actor pales next to the billion-year contract of service he signed with the Church of Scientology, according to a bombshell new book, “Going Clear: Scientology, Hollywood & The Prison of Belief.” New Yorker writer Lawrence Wright details Cruise’s demigod status within the church, as well as the group’s ultimate purpose — protect humanity from aliens living in our bodies, who are bent on destroying us and ultimately the planet.

Cruise was introduced to the religion when he was 23 years old by his then-girlfriend, actress Mimi Rogers. Seven years his senior, Rogers was an avowed member of Scientology; they married in 1987. Cruise was quickly intrigued, but he kept his initial participation low-profile. He began undergoing “auditing” — a process in which church members are queried about every aspect of their lives — under his given name, Thomas Mapother IV.

It took several years for church leaders to realize that for all of their celebrity acolytes — including John Travolta, Priscilla Presley, Kirstie Alley, Kelly Preston and Sonny Bono — they had a true superstar at their disposal.

Cruise would later come to believe that in the hierarchy of Scientology, he was No. 3, behind only the founder, the late L. Ron Hubbard (known as LRH) and No. 2 David Miscavige, who goes by COB, for Chairman of the Board of the Religious Technology Center.

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