Jerome Harmon, better known as J-Roc, is an American songwriter and music producer from Fort Worth, Texas. He frequently collaborates with Timbaland. Jerome Harmon has produced for Beyoncé, Justin Timberlake, Jay-Z, Chris Brown, Keri Hilson, Ashlee Simpson, Mario, Nelly Furtado, Jamie Foxx, Michael Jackson, Kat Dahlia and Chris Cornell.