Most of you will know plenty about the actress-turned-popstar-turned-TV talent judge, but for those wanting a primer on Simon Cowell's latest catch, here are ten fast facts to get you started.
1. Demi was born Demetria Devonne Lovato on August 20, 1992 in Dallas, Texas to dad Patrick and ex-Dallas Cowboys cheerleader mum Dianna Hart de la Garza.
2. She made her acting debut on Barney & Friends - starring in seasons seven and eight alongside fellow singer/actress and friend Selena Gomez.
3. Demi and Selena hosted their own YouTube vids titled The Demi and Selena Show where they shared their friendship and kept in touch with fans.
4. Lovato's credits included guest slots on Prison Break and Just Jordan, before a role in Disney's As the Bell Rings, which featured the track 'Shadow' that she had written herself. On a fateful day in 2007 she auditioned for parts in TV movie Camp Rock and series Sonny with a Chance. She won both, becoming a household name soon after.
5. The Camp Rock soundtrack featured four Demi songs, including Joe Jonas duet 'This Is Me'. Jonas went on to co-write much of Lovato's debut album Don't Forget with her.
6. Demi's a big fan of tattoos. Her body art includes the words 'You Make Me Beautiful' on her side, 'Stay' on her right wrist and 'Strong' on her left wrist.
7. If you thought those last two tats sounded a bit heavy, you'd be right. Demi was admitted to rehab in November 2010 for 'physical and emotional issues' and later said that the stint saved her life. She flirted with the idea of quitting showbiz but thankfully changed her mind.
8. While she was on the mend, Lovato spoke about her issues in an MTV documentary, for ABC's 20/20 and in her monthly column for Seventeen. "My goals for my fans? It's to really inspire people," she said. "That's all I hope to accomplish. If there is a young girl at home dealing with the same issues that I'm dealing with, I want to be able to reach out to her and tell her that it's going to be okay."
9. She has received support from the likes of Cheryl Cole, old pal Selena, Miley Cyrus, Kim Kardashian and Robin Roberts, but we don't know if Sir Paul McCartney is so keen on her after she nearly ran him over! "I can't believe I almost ran over a Beatle," she later quipped.
10. Demi in numbers: Three top-five studio albums. Two top-five soundtracks. Five Teen Choice Awards. Two People's Choice Awards and a whopping seven Hollywood Teen TV Awards. Pretty impressive for someone who's not even reached their 20s!