While promoting her new film Lion, actress Nicole Kidman has come out to explain that she feels the movie is like a "love letter" to her two grown-up adopted children, Isabella and Connor, whom she brought up in her 20s during her marriage to Tom Cruise.

Nicole KidmanNicole Kidman stars in a new film, Lion

Lion depicts the true story of a five-year-old Indian boy who found himself on a train 1,000km from his family.

Eventually little Saroo is adopted by an Australian couple who love him until one day he decides he wants to find his birth mother again.

Of course, the film resonated with Australian actress Kidman because of her own experiences with adoption.

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Speaking to the Guardian, Kidman, who plays Sue Brierley in the film, said playing a mother who adopted made her remember her wonder about the background of her two eldest children.

She said: "From the minute I held them, I wondered about that. Of course. Because you’re all intertwined. Your destinies somehow all come together."

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Kidman, who also has two biological children with her new husband musician Keith Urban, split from Cruise after 11 years together and her older children chose to grow up with him.

When asked what she felt for her children, Kidman said: "Love. Exactly what Sue felt, which is why I wanted to play Sue. The simplicity of that love.

"The gift of a child. And again, Sue has that absolutely simple, loving feeling.

"I’m getting into personal things now. Their own lives, their choices. But their love is profound."