Here's some more...

Singers...
Jerry Vale was born Gennaro Luigi Vitaliano
Bobby Darin's real name was Walden Robert Cassotto
Frankie Avalon was Francis Avallone
Lou Christie was born Luigi Alfredo Sacco
Glen Danzig was really Glenn Anzalone
Bobby Rydell was really Robert Ridarelli
Perry Como's was born Peter Costello
Nikki Sixx was really Frank Feranna Jr.
Frankie Cannon was born Frederick Anthony Picariello

Pianist George Greeley was born, Georgio Guariglia
Drummer for KISS Peter Criss was born George Peter Criscuola
jazz saxophonist Joe Farrell was Joseph Firrantello
comedian Joy Behar is Josephina Occhiuto

Actors...
Nicholas Cage is really Nicolas Coppola
Penny Marshall's surname was really Masciarelli
Vince Edwards was born Vincent Zoine
Anne Bancroft's real name was Anna Italiano
Robert Blake was Robert Gubitosi
Ron Carey was Ronald Cicenia
James Darren was James Ercolani
Connie Stevens was Constance Ingolia

....The list is never-ending.