Jessie J - Forest Live 2014 - Tickets on Sale at Viagogo.co.uk. And more Born Jessica Ellen Cornish on 27 March 1988 in Essex, Jessie J started her showbiz career performing in Andrew Lloyd Webber’s West End show Whistle Down the Wind. After graduating from the prestigious BRITS school in the same class as Adele and Leona Lewis, Jessie J found success as a songwriter, penning hits like ‘Party in the USA’ for Miley Cyrus.