The 25-year-old was rushed to hospital after suffering 'what appears to be' an overdose, according to TMZ.
Her celebrity friends, including Ariana Grande, Ellen DeGeneres and Lili Reinhart have all tweeted their love to the star.
Demi has battled addiction, mental illness and an eating disorder for years.
In 2011, the entertainer entered rehab, where she was also treated for bipolar disorder, bulimia, self-harm and addiction.
If you, or anyone you know, is seeking support contact Kids Helpline on 13 11 14 or visit the website.
