Bobby Darin ( born Walden Robert Cassotto ; May 14 , 1936 - December 20 , 1973 ) was an American singer , songwriter , and actor of film and television .
Walden Robert Cassotto ( May 14 , 1936 - December 20 , 1973 ) , better known as Bobby Darin , was an American pop singer , most famous during the 1950s .