Demi Lovato is grateful that music can get her through anything.

The 22-year-old singer took to Twitter to share her emotions with fans, posting messages that seemed to refer to her father, who passed away in 2013.

"I hate not knowing when you became an angel... I hate that you were alone (sic)," she wrote, adding that the lights started flickering as she was posting.

Luckily the star copes by listening to her favourite songs when things get tough. Specifically she thanked her friend and singer Sirah for her track Icarus.

"I'm so grateful one of my closest friends and such a special person in my life wrote this song.. That's what I love about music.. There's always a song to match what you're going through," she shared on Instagram.

"I didn't realize what this song was about until the second verse and that's when it really struck a chord with me.. Grabbed my heart in a way that not many songs can do. This girl is so incredibly talented and I'm honored to call her one of my best friends. I love you @sirahsays (sic)"

Demi's father struggled with mental health issues, which inspired her to join the Be Vocal: Speak Up for Mental Health campaign. It sees her team up with five mental health organisations to raise awareness.

"[The issue] is very important to me because I have struggled with bipolar disorder for several years now," Demi told People.

"Also my father had schizophrenia and bipolar disorder as well, and I watched him live a very unfortunate life because of the lack of access to treatment. So it's very personal to me. I just think mental illness is something people need to learn more about and the stigma needs to be taken away from."