Demetria Devonne "Demi" Lovato ( DEM-ee lə-VAH-toh; born August 20, 1992) is an American singer, songwriter, and actress. After appearing on the children's television series Barney & Friends (2002–2004), she starred in the Disney Channel short series As the Bell Rings (2007–2008). Lovato rose to prominence for playing Mitchie Torres in the musical television film Camp Rock (2008) and its sequel Camp Rock 2: The Final Jam (2010). The former film's soundtrack contained "This Is Me", her debut single and duet, which peaked at number nine on the US Billboard Hot 100.

After signing with Hollywood Records, Lovato released her pop rock debut album, Don't Forget (2008), which debuted at number two on the US Billboard 200. Its follow-up, Here We Go Again (2009), debuted at number one in the US, while its title track reached number 15 on the Hot 100. Her third studio album, Unbroken (2011), experimented with pop and R&B, and spawned the US top-ten single "Skyscraper". She released her self-titled fourth album in 2013, which debuted at number three on the Billboard 200, and contained the international top-ten song "Heart Attack". Lovato's fifth and sixth albums, Confident (2015) and Tell Me You Love Me (2017), infused soul and mature themes. She earned a Grammy Award nomination for Confident, while "Sorry Not Sorry", the lead single from Tell Me You Love Me, became her highest-charting single in the US, reaching number six. After a hiatus, she released her seventh and eighth albums Dancing with the Devil... the Art of Starting Over (2021) and Holy Fvck (2022), which respectively reached numbers two and seven in the US; the latter marked a return to rock-influenced music.

On television, Lovato starred as the titular character on the sitcom Sonny with a Chance (2009–2011), served as a judge on the music competition series The X Factor USA for its second and third seasons (2012–2013), appeared as a recurring character on the musical comedy Glee (2013–2014) and the sitcom Will & Grace (2020), and hosted her self-titled talk show and the docuseries Unidentified with Demi Lovato (both 2021). She also starred in the television drama film Princess Protection Program (2009), the animated films Smurfs: The Lost Village (2017) and Charming (2018), the musical comedy Eurovision Song Contest: The Story of Fire Saga (2020), and the documentary Child Star (2024); the last of which she also co-directed.

Lovato has sold over 24 million records in the United States and has also received numerous accolades, including an MTV Video Music Award, 14 Teen Choice Awards, five People's Choice Awards, two Latin American Music Awards, and a Guinness World Record; she was included on the Time 100 annual list in 2017. She co-founded the former record label Safehouse Records, under Universal Music Group, with singer Nick Jonas in 2015. An activist for various social causes, Lovato's struggles with an eating disorder and substance abuse have received considerable media attention, in response to which she published the self-help memoir Staying Strong: 365 Days a Year (2013) and released the documentaries Demi Lovato: Stay Strong (2012), Demi Lovato: Simply Complicated (2017), and Demi Lovato: Dancing with the Devil (2021).