(CNN) Nicole Kidman wants to keep adoption "very much a part of our conversation," and her latest role in "Lion" is doing exactly that.

Kidman adopted two children with ex-husband Tom Cruise and has two biological children with husband Keith Urban. She told CNN that her desire to have a family stemmed from her own "maternal instincts," which have been a "driving force" in her life since she was a young girl.

"I think because I've experienced motherhood in so many different ways," she said. "I've experienced adoption, birthing a child and I've experienced surrogacy. I'm like when it comes to it, I just wanna be a mama."

"I suppose my maternal instincts and drive has always been there since I was little ... and that's a huge driving force of who I am, which is why I probably played it out in so many different ways. I am a mother because I love being a mother."

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