"No," Cruise tells Diane Sawyer in an interview on ABC's "Primetime," airing Friday, 9 p.m. EDT. "No, I mean you can be Catholic and be a Scientologist. You can be Jewish and be a Scientologist. But we're just Scientologists."
The 27-year-old Holmes' switch to Scientology has sparked reports of a rift between her devout parents, Ohio, natives Martin and Kathleen, and the 43-year-old actor, who introduced her to Scientology.
However, Cruise shrugs off the stories of family friction, telling Sawyer he's close with "the whole family" and — "absolutely, yes" — they approve of Scientology.
The superstar dad-to-be also confirms to Sawyer that Holmes, in the final stages of her pregnancy with the couple's first child, will adhere to Scientology's practice of quiet birth. Cruise explains that "quiet birth," which aims to minimize talk and other noise inside the delivery room," is "basically just respecting the mother."
"She does what she's gotta do," he explains, addressing speculation that such a practice would somehow muffle Holmes completely and deny her pain medication. "If she needs medicine, she needs medicine."
The star of the upcoming "Mission: Impossible III" has two children, Connor, 11, and Isabella, 13, from his marriage to Nicole Kidman.
As the baby's birth approaches, Cruise says "it feels a little unreal."
Cruise said last week that he and Holmes plan to wed in the coming months. They have been engaged since June.