According to the calendar, Sigourney Weaver and Chevy Chase both celebrate birthdays on October 8. According to the folks who keep track of such things, neither the actress nor the comedian was born with those names. And according to word collector Paul Dickson, both Sigourney Weaver (née Susan Weaver) and Chevy Chase (Cornelius Crane) are sticking to an old Hollywood custom by adopting stage names.

For example, although few of us outside Tinsel town know the names Dianne Belmont, Melvin Kaminski, and Jerome Silverman, many of us know the Hollywood names of those three comedian-actors: Lucille Ball, Mel Brooks and Gene Wilder.

There are plenty of reasons why an aspiring actor might change his or her name. Stewart Granger changed his name from Jimmy Stewart because that name was already taken. William Henry Pratt changed his name to the scarier-sounding Boris Karl off before he took on the role of Frankenstein. And Eddie Albert Heimberger dropped his last name after he realized that he was becoming known as Eddie Hamburger. Of course, not everyone has to change their name in order to make it in Hollywood. Consider this roster of stars that rose to fame under their real names: Spencer Tracy, Katherine Hepburn, Jimmy Stewart (the one who kept his name), Humphrey Bogart, and, most famously of all, Ronald Reagan.