Now 88 years old, John Royce "Johnny" Mathis remains one of the last original crooners. Mathis, who sings popular standards and jazz, has put up some remarkable numbers over the course of his remarkable career. He’s sold something like 350 million albums worldwide and defies genres as he plays Brazilian music, Spanish music, soul music, rhythm and blues, soft rock, Broadway theatre, Tin Pan Alley standards and even disco. He performs tonight at 8 at MGM Northfield Park — Center Stage.