Complex sentence: Mason Jr. appeared on the 2011 season of American Idol as a mentor/producer, working with Pia Toscano and Jacob Lusk and worked as a mentor/producer on the 2013 season of "The X Factor USA".
Split into simpler sentences: Mason Jr. appeared on the 2011 season of American Idol as a mentor/producer, working with Pia Toscano and Jacob Lusk. He also worked as a mentor/producer on the 2013 season of "The X Factor USA".