02/21/2011 at 12:00 PM EST
There are some things that come easily for Nicole Kidman
– for instance her ability to tap into a character when the cameras are rolling. But when it comes to motherhood, the Oscar winner – and current best actress nominee
– says there is something she has always struggled with.
The mother of four, who just welcomed baby Faith
on Dec. 28 via a gestational carrier, says she has "had a roller coaster ride with fertility."
"Anyone that's been in the place of wanting another child or wanting a child knows the disappointment, the pain and the loss that you go through trying and struggling with fertility," the Rabbit Hole
actress, 43, tells Australia's 60 Minutes
in an interview set to air Sunday night. "Fertility is such a big thing, and it's not something I've ever run away from talking about."
It's a struggle that dates back to her marriage with Tom Cruise
– whom she divorced in 2001
after adopting kids Isabella, 18, and Connor, 16. In 2007, the actress revealed she had a miscarriage
before they split.
After giving birth to daughter Sunday Rose
, now 2½, her first child with husband Keith Urban
, Kidman says the couple used a surrogate because of her fertility struggles.
"We were in a place of desperately wanting another child," she says. "This opportunity arose for us, and I couldn't get pregnant."
Now as the family settles down in their homes in Nashville and Los Angeles, Kidman says she enjoys time with all of her kids equally.
"Children are children – you'll die for your children," she says. "And when you feel that as a parent – that's the unconditional love."