"A lot of my friends tease me." she told the May issue of Vanity Fair, in which she features on the cover.
The Moulin Rouge actor is married to Keith Urban, a singer and music producer who does world tours with his country music and the couple have two children - Faith, 8, and Sunday, 10, who attend church with their parents.
Nicole Kidman told the magazine: "That's how we are raising our children. Keith has his own beliefs but he comes, too.
"I had a very Catholic grandmother, and I was raised praying, so that had massive impact. I wouldn't say it's absolutism, there's constant questioning - I'm a willful, feisty girl.
"For me it's very important that I don't have judgment. My dad would always say, 'Tolerance is the most important thing.'"
Kidman has previously spoken about how she considered being a nun when she was younger and received critcism for acting in The Golden Compass because of it's anti-Catholic themes.
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