The award-winning actress was pictured arriving at the festival by boat in the waist-cinching dress that featured a black velvet mermaid skirt and a tulle corset covered in black sequins.
Babygirl follows Nicole's high-powered CEO who puts her career and family on the line when she begins a torrid affair with her much younger intern.
It also stars Harris Dickinson and Antonio Banderas, and she was joined by the pair at the red carpet as well as director Halina Reijn, but her family, who have been by her side in recent months, were absent.
"I'm willing to travel, which a lot of people are not," she told the outlet. "My kids are willing to travel… maybe less so now [that they're older], but they're very interested in the world, too."
"They say they've got so many stamps on their passport, more than most people that are in their eighties," Nicole continued. "That's because when they were little, they lived in Morocco and then we went to the Algerian Desert, where they were riding camels and in the souks for three and a half months."
Keith Urban and Nicole Kidman with daughters Sunday and Faith
She added: "They've lived in France, Australia, England, Scotland, Ireland, Asia, Vietnam, Hong Kong, all over."
"They've been out, I've been taking them out at different times individually. And it's been great to have them out on the bus," Keith once said of having his girls on the tour bus.
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