Actress Nicole Kidman refused to utter a scripted racial slur in her new erotic thriller The Paperboy because she didn't want to disrespect her adopted African American son Connor.

Director Lee Daniels tried to push the star, who plays prisoner John Cusack's lover in the upcoming movie, into sticking to the script and using the derogatory term "n**ger" as it seemed appropriate for her trashy character.

However, the Oscar winner drew the line and the two became embroiled in a heated argument over her strict stance - and now Kidman reveals it was all to avoid offending her teenage son and his culture.

At a press conference for the film, she told reporters, "I have a son who is African American. I just didn't feel like it was right."

And Kidman hopes Daniels understands she wasn't trying to be rude by defying his wishes.

She added, "What I try to do as an actor is fulfil a directors vision. I have opinions, but at the same time I'm not there to stop him from anything. I've really tried to do that in every film. I never want to pull them off their vision."

And Daniels tells Wenn his producers urged him not to push Kidman too far on the script slur - because she was really taking risks in other parts of the movie.

He explains, "They said I shouldn't complain because my producer said, "Day one she was bent over having sex on a washing machine with John Cusack. (On) day two she urinates on Zac Efron and (on) day three she has telepathic sex, so I think you could forgive her for the N word'."