Al Jolson (born Asa Yoelson in Seredzius, Lithuania on May 26, 1886 October 23, 1950) was an American singer and the son of Jewish immigrants. He was one of the most popular entertainers of the 20th century.
The son of a Jewish cantor, Jolson became a popular singer in New York City in 1898, and gradually developed the key elements of his performance: blackface makeup; exuberant gestures; operatic-style singing; whistling and directly addressing his audience.
http://en.wikipedia.org/wiki/Al_Jolson