The "Big Little Lies" star's two adopted children, Isabella and Connor, opted to live with her ex-husband after their divorce in 2001, and started becoming regulars at his church.
Nicole, who is not a Scientologist, has been private about her relationship with her kids over the years, but in a new interview with Australia's Who magazine she insists she has nothing but love for them.
"I'm very private about all that," she says. "I have to protect all those relationships. I know 150 per cent that I would give up my life for my children because it's what my purpose is."
And although she may not agree with all their life decisions, she stands by her kids.
"They are adults (now)," she adds. "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."
She continues, "I think that's so important because if that is taken away from a child, to sever that in any child, in any relationship, in any family - I believe it's wrong. So that's our job as a parent - to always offer unconditional love."
Nicole also has two young daughters with country singer Keith Urban, who she wed in 2006.