Nicole Kidman and Keith Urban sing at hospital

In a touching impromptu display, country music star and "American Idol" judge Keith Urban and his wife Nicole Kidman sang Amazing Grace at a hospital in Melbourne.

The entire staff began singing with the duo but when it got to the second verse, the husband and wife took over at the Monash Children's Hospital on Friday, reported Channel 4 News.

The Australian power couple also visited patients and left an acoustic guitar, signed: 'With love Keith Urban and Nicole Kidman', for the hospital's neonatal intensive care ward ahead of Friday night's Celebrate Life Ball, which the couple flew in to attend, reported Mail Online.

The hospital tweeted their thanks: "Thank you again to the amazing Nicole Kidman and @KeithUrban for brightening the day of our patients this afternoon. #celebratelifeball'.

Kidman was raised in Australia,while Urban is from New Zealand.

Source: Channel 4 News, Mail Online