Di'Jonn Grizzell, (born August 29, 1989) better known by his stage name Jonn Hart. is an American R&B singer from Oakland, California. He is a former member of the band Tha Outfit and was formerly signed to Epic Records. His debut release, "Who Booty", has been in regular rotation on radio stations, peaked at #1 on the Rhythm Radio Music Chart, and debuted on the Billboard top 40 pop charts in December 2012.