Sia’s songwriting skills allow her to make catchy hits for herself and other artists, and she shows this talent and her vocal ability yet again on her latest holiday album, Everyday Is Christmas.

The surprise performance of the 2011 classic happened on the festival's main stage during a headlining set by Afrojack.

Sia has disclosed that she gave birth to her third child, Somersault Wonder Bernard, last year. The father of her child is ...