It seems that, for Kidman, it's actually Urban's ability to stay cool, calm and collected that has made their bond so strong.
The Big Little Lies star recently opened up in an interview with WSJ. Magazine for the publication's upcoming May issue and revealed her sweet nickname for her handsome husband, which celebrates his chillness.
According to Kidman, she lovingly refers to Urban as her "mellow muso" -- muso being an Australian slang term for musician.
"He’s pretty much the flip side of neurotic," Kidman said, adding later that he would always be the first person she'd call in the event of a crisis or emergency.
The actress also revealed that it's not just staying level-headed that has kept their family united. Kidman said that she and her husband, who have two daughters -- Sunday, 11, and Faith, 9 -- have "a system worked out to keep the family together."
"When Keith’s not touring, it’s much easier. He’ll be on tour next year, and then I just don’t work as much. Literally -- it will become imbalanced, and we will change it," Kidman said, explaining that she will "pass on films" to make sure they maintain their work–life balance.
"We don’t have the answers, but the one thing we do know is that we will not jeopardize us," Kidman added.
It's clear that love and emotional connection play a big part in Kidman's personal philosophy of life. When asked what she would consider the best bit of advice she's ever received, Kidman shared, "When you get to the top, just remember there's nothing there. The only thing that really matters is love."
"No matter what your accomplishments are, it's incredibly lonely if you're not surrounded by some form of love," she said.
"[We've had] lots and lots of family time, and I've actually been really enjoying that, honestly. [We are] just being creative as a family with how we use our time and help other people in any ways we can do, even if it is something like an at-home concert," Urban said. "It's our little bit to try and help out."
Check out the video below to hear more from Urban about his time in self-isolation with his loved ones.