Nicole Kidman believes it's natural when adoptive children want to find out about their birth family.

The Australian actress is currently promoting her new film, Lion, about a couple which adopts a young Indian boy who loses his parents after getting lost on a train. Nicole plays Sue Brierley, who becomes mother to Dev Patel's Saroo. As he grows older, Saroo wants to learn more about his family, and sets out to find them.

Nicole's experience with adoption extends beyond the set of Lion, and she shares adopted children Isabella, 23, and Connor, 21, with her ex-husband Tom Cruise. While the 59-year-old usually remains tight-lipped about that side of her life, she did shed some light on the matter during a chat with InTouch magazine.

"Every family's experience with this is distinct and private," she began. "But we live in an ever more transparent world, technologically speaking. Kids are resourceful and the need to know your origin story is universal."

In a 2014 interview with Australia's Woman's Day, Connor denied rumours suggesting he was estranged from Nicole, sharing, "I don't care what people say. I know that me and mum are solid. I love her a lot. My family means everything."

Two years later, Isabella told New Idea magazine she still talks to both her adoptive parents, despite speculation suggesting otherwise.

Nicole went on to have biological daughters Sunday, eight, and five-year-old Faith with her second husband Keith Urban, and admits the premise of Lion resonated with her on an emotional level.

"It's about the power of mothers - whether they are biological of adoptive. It's very personal for me," she said.

Lion is based on true events and premiered at the Toronto International Film Festival earlier this month (Sep16). It's director Garth Davis' big screen debut, and hits cinemas from 24 November (16).