UNION RULES. KEATON WANTS TO GO BACK TO HIS ORIGINAL NAME. >> Reporter: THE STAR HAS ADOPTED A NEW STAGE NAME. >> I'M GOING TO MAKE YOU SO HAPPY. >> Reporter: NO LONGER JUST MICHAEL KEATON, HE IS ADDING HIS REAL LAST NAME. REVEALING TO "PEOPLE" HE CHANGED HIS NAME IN THE 1970s PICKING MICHAEL KEATON OUT OF THE PHONE BOOK BECAUSE THE SCREEN GUILD DO NOT ALLOW YOU TO USE THAT NAME FOR CONFUSE. THERE WAS ALREADY A FAMOUS MICHAEL DOUGLAS. MICHAEL KEATON DOUGLAS IS USING HIS NEXT PROJECT, BUT AMID THE STRESS OF MAKING THE FILM, HE FORGOT TO GIVE THEM ENOUGH TIME TO PUT THEM IN. NAME CHANGES HAVE A LONG HISTORY IN HOLLYWOOD. ♪ DIAMONDS ARE A GIRL'S BEST FRIEND ♪♪ >> Reporter: BEFORE MARILYN MONROE, SHE WAS NORMA JEAN BAKER. >> MY REAL NAME IS EMILY. WHEN YOU REGISTER A BUSINESS AND CAN'T HAVE THE SAME NAME AS SOMEONE ELSE. >> Reporter: IN MUSIC, NAMES TURN CREATIVE. >> WHEN DID YOU GO WITH JOHN LEGEND? >> IT WAS A NICKNAME. >> Reporter: FOR A PERIOD OF TIME, PRINCE CHOSE TO GO BY THIS UNPRONOUNCEABLE LOVE SYMBOL. >> WELL, MY NAME IS VERY SPIRITUAL TO ME. >> Reporter: THAT WAS WAY TOO CONFUSING FOR FANS AND HE CHANGED IT BACK. IT JUST GOES TO SHOW, IN THE VAST WORLD OF SHOW BUSINESS, YOU CAN REINVENT YOURSELF OR AT LEAST YOUR NAME. NOW HERE'S THE THING, THE NAME MICHAEL KEATON DOUGLAS HAS NOT APPEARED ON ANY PROMOTIONAL MATERIAL. WE MAY NOT SEE IT UNTIL THE NEXT PROJECT. GUYS. >> THANK YOU, DANA. >> IS YOUR REAL NAME PETER ALEXANDER? >> GOOD EVENING. I'M PETER PINK. THAT HAD A NICE RING TO IT. >> ANGIE IS DYING. YOU CANNOT SEE HER OFF CAMERA. >> MY DAUGHTER TOOK IT AS A MIDDLE NAME. MY DAUGHTER'S MIDDLE NAME IS EMMA PINK. >> THE COOLEST NAME I'VE EVER HEARD. SHE NEEDS TO GO BY THAT PERMANENTLY. >> I'M