Joseph Thomas Elliott Jr. was born in Sheffield to Joseph William Elliott (1930–2011) and Cynthia Gibson. He was educated at King Edward VII School. Elliott met Pete Willis (a member of a local band called Atomic Mass) in November 1977 after missing a bus. Upon finding out that they were both musicians, Elliott met the rest of the Atomic Mass members. The band spent hours talking and listening to records in Elliott's bedroom. Elliott tried out as a guitarist and, though the band had not heard Elliott sing, they were impressed by "his attitude and his ideas about being in a band" and he became the band's vocalist instead. The other members also took Elliott's suggestion to change their name to "Deaf Leopard." Elliott had invented the name for a band in his youth. Tony Kenning suggested they change the band name to "Def Leppard" to distinguish them from contemporary punk bands like The Flying Lizards and Boomtown Rats. The band claims that any apparent similarity of the name Led Zeppelin to Def Leppard was unintentional. Elliott soon became an integral part of the band while also contributing his songwriting skills.