Singer songwriter Sia, 43, has made the shocking revelation that she suffers from chronic pain, Ehlers-Danlos syndrome, and an unnamed neurological disease.
Ehlers-Danlos syndrome is a very rare inherited condition that weakens the connective tissue in the body, leading to hypermobile joints and fragile, overly stretchy skin.
It only affects 1 in 5,000 people, and it can be life threatening.
The condition may be the cause of Sia's chronic pain - but it's unclear which neurological disease she is suffering from.
Sia is famously private, and even covers her face at most public appearances and in music videos.
But she opened up about her pain in a tweet dedicated to her fans who were also suffering, be it physically or mentally.
In a post to her 3.8 million followers, Sia wrote: "Hey, I'm suffering with chronic pain, a neurological disease, ehlers danlos and I just wanted to say to those of you suffering from pain, whether physical or emotional, I love you, keep going.
"Life is fucking hard. Pain is demoralizing, and you're not alone."
The Chandelier singer suffers from other health issues too, including Graves disease, an autoimmune disorder characterised by an overactive thyroid.
She said in an interview that thyroid hormone replacement therapy had hugely improved her health.
Sia has also struggled with addiction to painkillers and alcohol, and has been so depressed in the past that she contemplated suicide.
In 2010, she cancelled her upcoming public appearances due to extreme lethargy and panic attacks.
Last year she celebrated eight years of being sober with the tweet: "Eight years sober today. I love you, keep going. You can do it."
