Demetria Devonne "Demi" Lovato (born August 20, 1992)[2] is an American singer, songwriter, musician, and actress. Her earliest roles included Angela on Barney & Friends, before she became better known for her starring roles in the Camp Rock movies, as Sonny Munroe in Sonny with a Chance, and as the star of the 2009 movie Princess Protection Program. She is also involved in philanthropic activities through charity work and various social and environmental causes.