Arnold Dorsey (Humperdinck's real name) started his career in music in the 1950's under the name of 'Gerry Dorsey' and gaining some popularity in Britain.
In the year 1966 and after a decade struggling to get a hit in the charts, his friend and also manager Gordon Mills suggested to make a fresh start as 'Engelbert Humperdinck', a name borrowed from a XIX century German Opera Composer.
The new pseudonym brought very good luck to Dorsey and after two singles his version of 'Release me' became an international hit, staying in the number 1 position of the UK charts for 6 weeks.
Since then, Dorsey/Humperdinck's has had a successful career as a 'crooner' and is going to represent England in the 57th edition of the Eurovision Song Contest 2012.
Comedian Eddie Izzard explains the story of Engelbert Humperdinck's name change in this funny video:
www.youtube.com/watch?feature=player_embedded&v=cgfELLyP