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Now that her secret's out, Nicole Kidman can't stop raving about her newborn daughter Faith Margaret.

Born via surrogate on December 28 in Nashville, the Rabbit Hole star, 43, and hubby Keith Urban kept the news of their family's latest addition private until January 30.

"We have a new little baby," the Nina Ricci-clad actress told at the Screen Actors Guild Awards in L.A. Sunday. "It is beyond thrilling!"

As for any mini-milestones, "she is still only 5 weeks old," Kidman said. "She is kind of just looking around."

Speaking to E!'s Giuliana Rancic, the Best Actress nominee (she lost to Natalie Portman) explained how she and Urban, 43, chose their daughter's name.

"We needed to have that through the whole pregnancy. That's what it required -- a lot of faith."

"People call her just Faith, but she's actually Faith Margaret, that Southern double name," Kidman continued. "Margaret is my grandmother's name. She had her last baby at 49, so she's my inspiration."

How is the couple's two-year-old daughter Sunday Rose adjusting to becoming a big sister?

"She's so into [Faith] and she's crazy about her," Kidman told Access Hollywood. "We really wanted Sunday to have a sibling, so now we've got Sunday and Faith Margaret...we've got our hands full! We're really happy."