The couple - who already have two-year-old Sunday Rose together - admit they had an anxious wait for the arrival of their second daughter Faith Margaret, who was born on December 28 last year through a gestational carrier.
Nicole said through her spokesperson: "We spent Christmas on tenterhooks and after Faith Margaret was born on Dec. 28, a healthy 8 lbs 9 oz, we spent New Year`s on cloud nine."
Since bringing the new baby home, Nicole and Keith, both 43, have enjoyed having time to bond with their two daughters at their homes in Nashville and Los Angeles.
She added: "We have been having a wonderful bonding experience with Faith Margaret and feel truly blessed."
Friends close to Nicole - who also has adopted kids Isabella, 18, and 15-year-old Connor with ex-husband Tom Cruise - say she and Keith never gave up hope of having another child.
One pal said: "They never gave up faith they`d have another child together. They feel blessed. They-re just thrilled."
Announcing Faith`s birth on January 17, the couple released a statement saying: "Our family is truly blessed, and just so thankful, to have been given the gift of baby Faith Margaret.
"No words can adequately convey the incredible gratitude that we feel for everyone who was so supportive throughout this process, in particular our gestational carrier."