In an interview with the The Mail on Sunday the 46-year-old said her role as an actress meant that she was not involved with the film's plot and that she wishes she had met with Monaco's royal family while the film was being made to discuss the project's intentions.
"If I was producing the movie, it would be a different thing," said Nicole. "My loyalty has to be to the film and the director, that's where I stand.
Nicole Kidman at the Grace of Monaco premiere
"You can't get involved in all those things operating around a film when you are acting," she added. "Because that takes the energy away from the performance."
Nicole expressed regret that she didn't accept a lunch invitation from Monaco's Prince Albert II and his sisters Princess Stephanie and Princess Caroline, who wanted to discuss how the film would portray their late mother.
"They invited me for lunch," she explained. "But I was shooting six days a week and I had my small children and my mother and my aunt. I couldn't take all these people.
Nicole as Princess Grace
"Now subsequently I wish I would have gone, because I would have been able to explain to them the intentions," she added. "It's very threatening if someone plays your mother. But I would hope that they would know that there was an enormous amount of respect and love behind everything that was done."
Monaco's royal family criticise 'totally fictional' Grace of Monaco film
Nicole regrets not meeting with Princess Caroline, Prince Albert and Princess Stephanie (L-R)
The mother-of-four also revealed that during filming she discovered that she felt a lot in common with Grace.
"Not in terms of being a princess," she clarified. "But the gilded cage and motherhood versus career versus responsibility versus the desire to put good in the world. All of those things are very relevant to me.
"She [Grace] is very human in her desires and that is what surprised me in the script."
Nicole Kidman and Keith Urban
Speaking about her role as a wife and a mother, Nicole stressed that her family comes before her job and she always consults her husband Keith Urban before taking on a role.
"I know this sounds old-fashioned but I do put it on the table. Because if it won't work for us, then I'm not doing it," she said, adding that if Keith asked to choose between her family and her job, she would always pick the latter. "Yeah," she said. "If he asked me, no question."