Nicole Kidman was treated to a rendition of Happy Birthday from her husband Keith Urban and his entire concert audience.

The Hollywood actress turned 51 on Wednesday.

Urban was performing at the Country USA festival in America, where he encouraged everyone in the auditorium to sing to his wife.

Kidman posted a video clip on Instagram of the crowd serenading her.

At the end Urban turns to the camera and says: “I love you baby. Happy Birthday!”

“What a gift – my husband and everyone at @officialcusa Oshkosh WI singing me Happy Birthday!!!!!!” she said.

Kidman and Urban, 50, have been married since 2006 and have two daughters together.