The Oscar-winning actress and her husband, country singer Keith Urban, took Sunday Rose, six, and four year old Faith Margaret to see a matinee performance of Aladdin And His Wondrous Lamp.

During the show, the two youngsters were among four children selected from the audience to join the cast onstage for a song, and onlookers tell the Sydney Daily Telegraph that Sunday Rose impressed with her "pitch perfect" vocals on a rendition of Old MACDonald Had a Farm.

The production's executive producer Chris Wood tells the publication, "As a part of the show we pull four children out of the crowd and give them a prize and they get involved in singing Old MACDonald. Sunday Rose and Faith joined two other children on stage and sang along with Wishee Washee."