Sia Performs 'Titanium' with Brooke Simpson on 'The Voice' Finale (Video)

Sia wears a wig over her face and stands inside a box while performing on The Voice finale on Tuesday (December 19) in Los Angeles.

The singer joined The Voice finalist Brooke Simpson to perform a duet version of her song “Titanium.”

PHOTOS: Check out the latest pics of Sia

Sia later changed into a festive outfit to sing her holiday song “Snowman.” She made sure to wish fans a Merry Christmas and a Happy Hanukkah after her performance.

Want to see what Sia‘s face looks like? Check out the latest pics!