Nicole Kidman prays she will live "long enough" to see her children grow up.

Nicole Kidman

Nicole Kidman

The 49-year-old actress has young daughters Sunday, eight, and Faith, five, with her husband Keith Urban - as well as adopted children Isabella, 23, and Conor, 21, with ex-husband Tom Cruise - and has said that her biggest fear as an "older mother" is passing away before her children have finished growing up.

Speaking to American television show 'CBS Sunday Morning', the 'Eyes Wide Shut' actress said: "I'm an older mother, so you know. I would just like to be here long enough to... see my children grow up and thriving. 'That's all I ask, and that my husband and I are with each other. Simple. Simple requests."

And although the 'To Die For' star hasn't had biological children until later in her life, she recently revealed she "always knew" she would be an adoptive mother.

She said: "Because I always knew I'd adopt, I just always wanted a child. I think from a very early age, I wanted a child. I knew that I was going to have a child and that it didn't matter [how], I actually didn't know if I was ever going to give birth to a child. So that was the least of it for me. And what I did first was adopt."

Nicole is currently starring in 'Lion', a drama about a young boy who gets lost and ends up being adopted by an Australian couple, and says she took on the role because she connected to the story about the "bond between a mother and a child".

She said: "That's what I love about this movie, and what I keep trying to say.

"Once the bond is there between a mother and a child, the biological part of it is sort of the least important part. I think when that bond forms, it's astounding how powerful it is."