Nicole Kidman Says That Her New Movie About Adoption Is A amor Letter To Her Children 

Nicole Kidman‘s latest film role is one that’s deeply personal for the actress — because it involves a family that looks a lot like hers.

magazine, Kidman explains why she felt drawn to her character Sue in the upcoming drama

, that it was important to me because I’m a mother with adopted children,” she says. “This movie is a love letter to my children.”

tells the story of Sue’s adoptive son Saroo (played by Dev Patel), who as a young boy became accidentally separated from his birth family in India. As a young man, he tries to find them, using Google Earth to search for his home village. The movie, which premiered earlier this year at the Toronto International Film Festival, is based on Saroo Brierley’s personal story, documented in his non-fiction book

Kidman adopted her two older children, Isabella, 23, and Connor, 21 with ex-husband Tom Cruise. She is also mom to Sunday Rose, 8, and Faith Margaret, 5, with husband Keith Urban.

“[My character] Sue is deeply maternal and full of unconditional love, which is beautiful,” Kidman, 49, tells

. “That’s why I wanted to do it. I relate to that. I feel that for my own children who are adopted. It’s not about anything else other than ‘I wanted you.’ It’s that deep and personal, and whatever your journey is, I’m here to love and support you. That’s what I connected to.”

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Kidman, who posed for the magazine in Dior Haute Couture, also opens up about how she typically picks her roles, calling herself “the wild card.”

“I’m so spontaneous — sometimes to my detriment and sometimes my benefit — but it’s how I’ve always been,” she explains. “My husband [Urban] never knows what I’m going to choose. And then he’ll ask me to explain why and I can’t!”

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