The star will appear as "colourful charmer JACK EDWARDS" in the hit TV show from next year (06).
Essex - who starred in seminal 1970s rock movie THAT'LL BE THE DAY and its sequel STARDUST - is thrilled about the role, which will see him to return to his boyhood home, London's East End.
He says, "Coming from the East End it will be good to go back there."
Executive producer KATE HARWOOD enthuses, "David is an extremely gifted and charismatic actor. Jack is going to bring some real sparkle to the square."