Though she often hides behind her many wigs, Sia has never shied away from opening up about her personal struggles, whether in her lyrics or candid interviews.

In her high-profile 2013 cover story with Billboard, the This Is Acting artist spoke out about her alcoholism, which inspired her 2014 radio smash "Chandelier," as well as her addiction to medication.

"All I wanted to do was write for pop stars. For one reason or another it never happened for me," she shared. "Then I got seriously addicted to Vicodin and Oxycodone, and I was always a drinker, but I didn't know I was an alcoholic. I was really unhappy being an artist and I was getting sicker and sicker."

On Saturday, September 10, the Australian singer-songwriter celebrated reaching six years of sobriety on Twitter, writing, "6 years sober today. Thank you to all those who have contributed knowingly and unknowingly. I love you, keep going."

Back in February, "The Greatest" singer appeared on The Late Late Show with James Corden where, during her "Carpool Karaoke" segment, she addressed her battle with alcohol, telling the host about her decision to cover her face, “I was an alcoholic and a drug addict, and I sobered up and decided I didn’t want to be an artist anymore because I was starting to get a little bit famous, and it was destabilizing in some way. So I thought, what doesn’t exist in pop music at the moment? And it was mystery."

In 2010, Sia announced that all future recording, promotional events and tours would be cancelled due to struggling with her increasingly poor health, and she revealed that she was considering retiring from music altogether. Months later, however, the artist shared that after finally being correctly diagnosed with hyperthyroidism, she was on the path to managing her autoimmune condition.

She has since returned—and quite successfully—to pop music stardom.

Yes, Sia Has a Face — This Is What It Looks Like: