Jessie J is a pseudonym of, at least, two artists: 1. A singer songwriter from the United Kingdom 2. A rapper from the United States 1. Jessie J (born Jessica Cornish on 27 March 1988) is a singer-songwriter from Essex, England, United Kingdom. She began a solo career after working as a songwriter and backing vocalist for artists such as Miley Cyrus and Christina Aguilera. Her debut album, "Who You Are", was released in 2011 and contains the singles "Do It Like A Dude"