Sia Shocks ‘American Idol’ Finalists as She Reveals Her Face: Watch

Sia unmasked! The “Chandelier” singer and songwriter, 40, surprised the final four contestants on American Idol when she revealed her face during rehearsals on Thursday, March 24 — but she still hid from viewers behind her trademark wig during the show.

As Sia mentored the finalists (La’Porsha Renae, MacKenzie Bourg, Trent Harmon and Dalton Rapattoni), she teared up as they rehearsed some of her own songs, including “Elastic Heart.”

“You’re gonna make me cry!” the Australian star told Renae, before telling the camera, “I stood before these kids and they were singing songs that I had written, and I kinda wanted to cry. It was much more meaningful than I had anticipated. It was really quite moving.”

Sia performs on 'American Idol'
Sia performs on 'American Idol' airing on March 24, 2016. Ray Mickshaw/FOX

The starstruck contestants were touched by Sia’s emotion, raving about her advice and beauty.

“To see her in the flesh is kinda like seeing a unicorn,” Harmon noted, while Renae gushed about the singer’s blue eyes and “beautiful” face.

Sia also treated viewers to a performance of her own, singing her song “Cheap Thrills” in a purple dress with a huge bow atop her multicolored wig.

In October 2013, the very private musician wrote an op-ed titled “My Anti-Fame Manifesto” for Billboard, where she explained that she hates fame and likes to stay out of the spotlight.

Sia performs on 'American Idol'
Sia performs on 'American Idol' airing on March 24, 2016. Ray Mickshaw/FOX

“If anyone besides famous people knew what it was like to be a famous person, they would never want to be famous,” she wrote. “Imagine the stereotypical highly opinionated, completely uninformed mother-in-law character and apply it to every teenager with a computer in the entire world. Then add in all bored people, as well as people whose job it is to report on celebrities. Then, picture that creature, that force, criticizing you for an hour straight once a day, every day, day after day.”

Sia has also spoken out about her past struggles with depression, bipolar disorder and drug and alcohol addiction. She told OK! magazine that she considered attempting suicide in September 2010, shortly before she entered a recovery program. The entertainer attributes her decision to hide her face to her sobriety.

Sign up now for the Us Weekly newsletter to get breaking celebrity news, hot pics and more delivered straight to your inbox!

Want stories like these delivered straight to your phone? Download the Us Weekly iPhone app now!