It's no secret that Demi Lovato has been through some tough times. The chart-topping pop singer has made no bones about it, sharing stories of her struggles with drugs, alcohol, and bulimia with her fans and the media. In fact, the reason the singer was chosen to sing "Let It Go" – the emotive, Oscar-winning song from Disney's animated film, "Frozen," about overcoming adversity – is because she transcended her tumultuous past.

While the version of "Let It Go" that appears in the film was sung by Broadway star Idina Menzel, Disney decided to ask Lovato to sing a second version of the song to be used as a single. "It just so happened that Demi was part of the Disney family already, and that she had a past that she’s pretty open about that is similar to Elsa’s journey of letting a dark past and fear behind and moving forward with your power,” songwriter Kristen Anderson-Lopez told the Wall Street Journal, comparing Lovato's journey to that of the film's protagonist.

The uplifting song also resonated with Lovato, who said in a statement, "It's so relatable. Elsa is finding her identity; she's growing into who she is and she's finally accepting her own strength and magical powers. Instead of hiding it, like she's done all her life, she's letting it go and embracing it."

https://www.youtube.com/watch?v=kHue-HaXXzg

Twenty-one-year Lovato started out in show business as a child, starring in "Barney and Friends" and later in the 2008 Disney Channel movie, "Camp Rock," with the Jonas Brothers. She later admitted to being bullied as a child and teased about being overweight, which led to her eating and cutting disorders. In a candid 2011 "Good Morning America" interview, Lovato explained how she overcame these issues by getting professional treatment and wanting to set a good example for her younger sister.

Lovato's version of the show-stopping "Let It Go" has sold more than one million copies to date and has been certified platinum.