Nicole Kidman was Keith Urban’s “baby girl” long before she signed on for the movie of the same nickname.

The Oscar winner, who then stars in the erotic drama Baby girlrevealed to W Magazine for The Art Issue that her country star husband, 57, is already calling her the nickname and even inked it.

“He actually has ‘babygirl’ tattooed on his neck,” Kidman, 57, said, adding: “Keith isn’t allowed to call anyone else babygirl. But now, thanks to the movie, it has taken on a different meaning. So he says, ‘No, I still have full rights over Babygirl!’ ”

Kidman married Urban in 2006 and they share two daughters, Sunday, 16, and Faith, 13.

The actress added that she doesn’t know if Baby girl writer-director Halina Reijn even knows the nickname coincidence. “I don’t know if Halina knows that, but it’s all part of kicking up fairy dust,” she said.

In Baby girlKidman stars as a powerful CEO named Romy, who risks her career and family to pursue a kinky affair with an intern, played by Harris Dickinson, 28. The film also stars Antonio Banderas, and the trailer mentions Dickinson’s character Romy a “good girl” and later says: “You are my little girl.”

Kidman remembered that W Magazine how the project came to her attention. “I knew Halina Reijn and I heard she was directing a film called Baby girl. I was in Australia and called Halina, and we didn’t answer the phone for almost two hours. From that moment on we made the film together.”

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“Playing this character didn’t scare me at all,” said Kidman, who won the best actress award at the Venice Film Festival for her performance. “It fascinated me. It drew me in. I wanted to make sure I fulfilled Halina’s vision.”

“But on the first day,” she added, “I started saying, ‘This is going to be very revealing.’ And there were several moments where it was like, “I don’t want to be looked at anymore, I don’t want to be touched in any way.” ”

Baby girl can be seen in cinemas from December 25.