Nicole Kidman and Keith Urban divorce rumors have been hounding the couple but it doesn't stop them from visiting a children's hospital in Australia, as they sang an impromptu duet of "Amazing Grace."

According to the report by People, the "Grace of Monaco" star and the "American Idol" judge was at Monash Children's Hospital in Clayton, Victoria on Friday the 13th. They then gave a treat the patients and staff with a rare "mini-concert."

The country singer brought along his guitar and sang "Amazing Grace" with Nicole Kidman, who earlier showed she can sing with a duet with Robbie Williams for the 2001 hit revival "Something Stupid."

The grateful hospital administration wrote a statement which read: "We want to say a huge THANK YOU to Nicole, Keith and Swisse [Wellness, a vitamin company] for lifting up the spirits of some of our most deserving patients, families and staff."

Hospital spokesman Shane Butler told smh.com that the staff was "thrilled" about the visit, which was not announced.

"There was a real buzz in the air," he added.

With the Nicole Kidman and Keith Urban divorce rumors chasing them wherever they go, the couple seems to put up a brave front as they travelled together a lot lately, including the CMT Music Awards on June 4, People noted.

The National Enquirer on its May 26 issue claimed that Nicole Kidman and Keith Urban's divorce may be staved off because they will try to have another baby again. The couple has two daughters--Sunday, 5, and Faith, 3-and Nicole Kidman also has two older kids she adopted with ex Tom Cruise.

"Keith is hoping for a son. And the plan is already bringing them closer together," the tabloid said.

Last month, the Star first reported of a possible Nicole Kidman and Keith Urban divorce not only because of their busy careers but also because the country star is an unapologetic flirt, even with his "American Idol" co-judge, Jennifer Lopez.