In 2008, 11-year-old Cody Simpson opened a YouTube account and began posting videos of his own musical performances. Accompanying himself on the acoustic guitar, the Australian preteen sang songs by other artists -- namely pop stars like Jason Mraz and Justin Timberlake -- while also giving some airtime to his original tunes. Producer Shawn Campbell stumbled across his YouTube page one year later and invited Simpson to the U.S., jump-starting a series of songwriting collaborations and studio sessions that resulted in a 2010 deal with Atlantic Records. His debut single, "iYiYi," was released later that year and cracked the Top 20 in Australia, thanks in no small part to a cameo by Flo Rida. Two versions of the song were later featured on 4 U, Simpson’s debut EP, which appeared in December 2010. ~ Andrew Leahey