The country singer and his movie star wife charm a small crowd with their rendition of "Amazing Grace"

By Katie Kauss
Updated June 16, 2014 08:10 PM

Who says Friday the 13th is an unlucky day? Definitely not the patients and staff at Monash Children’s Hospital in Australia, who were treated to mini-concert with Keith Urban and Nicole Kidman last Friday. Sitting on a desk in the hospital’s NICU, Urban strummed the guitar and sang with some help from his wife (and the starstruck NICU staff) in a rare duet.

“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,” the hospital wrote in a statement on its website Monday.

Later that day, Kidman and Urban attended the Swisse Wellness Australia Celebrate Life Ball in Melbourne, where Kidman playfully donned a black masquerade mask.

The couple has been traveling quite a bit lately, surfacing in Nashville on June 4 for the CMT Music Awards and staying in town for Urban’s CMA Fest performance that weekend before heading to their native Australia.