Elvis Presley is undoubtedly the King of rock 'n' roll. His music, a mash-up of country, gospel, and rhythm and blues, not only revolutionized the 1950s and beyond, but his distinct voice, electric dance moves, and magnetic persona did too. Beyond his influence on music, his talent graced the big and small screen, and he defined what it meant to be a triple threat. Today, his legacy is synonymous with the word icon, and it's hard to believe during his lifetime that anyone else could outmatch his talent. However, Presley would go on to praise, towards the end of his life, one other performer, whom he called the world's greatest singer.