The 24-year-old singer took to social media to share the results of a DNA test she took, which showed that she has Spanish, Native American, Scandinavian, Irish, British and African ancestry but was upset when some people reacted negatively.
She tweeted: "I did a DNA test and found out I'm mainly Spanish, with Native American, SCANDINAVIAN (which I had NO idea), Irish, BRITISH...."
"And I'm 1% African!!!!"
"I didn't do a DNA test a few years ago, I only found out from my uncle about certain places (sic)."
While the majority of Demi's fans reacted positively, she was left upset by some negative comments and wrote an angry tweet.
She said: "Just thought it was cool and totally random. Some of y'all are mean af. Twitter sucks (sic)."
Meanwhile, inspired by her own mental health struggles, Demi recently decided to sign up to executive-produce a documentary called Beyond Silence, which follows three people suffering from three very different mental health issues.
She said: "I hope that this film will show people that there is nothing wrong with having a mental health condition. If you do have one, you are able to live well and thrive with a mental health condition, if you are able to speak up and be vocal about the things you are going through.
"There's something about when you speak out and are vocal about your story, it's very inviting to others who are dealing with the same thing. And if you can make that impact on somebody's life, it does something for you spiritually that makes you want to tell the story again and again and again.
"It's very important we create conversations, we take away the stigma, and that we stand up for ourselves if we're dealing with the symptoms of a mental illness. It is possible to live well and thrive with a mental illness."