In 2010, the Heart Attack hitmaker checked into a treatment facility to battle her addiction and depression issues.
Not only did she come out of the experience sober, but she also gained a new outlook on her relationships, and credits her showbiz friends with helping her through the struggle.
Lovato tells Access Hollywood, "I lost friends when I came out of treatment because I realised who wasn't there for me. I can list about five or six people that called me and made sure that I was okay."
Among them was Gomez, who has been her best friend since the age of 10, as well as Cyrus and Taylor Swift.
She adds, "Selena was there for me. She called me crying and I was like, 'Why are you crying?' Taylor Swift sent me an email saying, 'Hey, I don't know if you have a phone right now, but are you okay? Miley, too. But there weren't many more than that."