They got together in 1962 and their first hit was "Little Latin Lupe Lu".
Their career together lasted 40 years.
Bobby Hatfield was found dead in his hotel room in Kalamazoo, Michigan on November 5, 2003, half an hour before he was due to perform a concert with Bill Medley at Western Michigan University's Miller Auditorium. The cause of his death was attributed to cocaine and not simply, as first suspected, heart failure, according to the autopsy report.
Some of their other songs were "Unchained Melody", "Ebb Tide", "(You're My) Soul and Inspiration" and "Rock and Roll Heaven".
Their biggest hit was "You've Lost That Lovin' Feelin'" which remains the most played song in radio history, estimated to have been broadcast more than eight million times.
Bill Medley is still performing.