The Brit behind Miley Cyrus' "Party in the U.S.A", Jessie J, has stepped out into the light to claim her own fame. Born Jessica Ellen Cornish on March 27, 1988, Jessie knew that she had art running through her blood. After attending Colins Performing Arts, Jessie was cast at Andrew Lloyd Webber's West End play "Whistle Down the Wind" at the age of 11.