Young Chuck Levine had to change his name. Who ever heard of a Jewish comedy writer from New York City?
Rhymes with “rhyme”, more or less. The initial consonant is a sort of “kh” sound.
Properly, the “Ch” is a back-of-the-throat guttural, as in German “ach”. The rest is “ahh-eem”, which may be kept as separate sounds or elided into a single sound. I suspect different people prefer different pronunciations. In light of what people said above, I suspect the producer pronounces it “Charles”.
Or a British barrister.
I myself have gone through a name change. My last name is very unusual, hard to pronounce and even harder to spell. When I went into broadcasting, my first boss (as well as my second and third) urged me to use an “air name” so neither I nor anyone else would indavertently stumble over pronouncing my real name.
Some of my fellow deejays took air names because they wanted to keep their private and public lives separate. One woman I worked with received several overenthisastic love letters from a prison inmate.
Interesting that Emilio Estevez didn’t make the change, too. Do you know why he didn’t?
If you are making a horror movie, would you rather the lead was played by Boris Karloff, or William Pratt?
Or perhaps, someone told them, and they refused the advice.
IIRC, she was already billed as Natalie Portman when she did The Professional in 1994, she would have only been 12/13 at the time, so her mother, he is also her agent, probably did the name change.
Or perhaps these days people don’t care as much about their tv/movie persoanlities having hard to say, and thus assumed to be non-American, names.
Nicholas Cage changed his name from Nicholas Coppola, he’s Francis Ford Coppola’s nephew, to avoid nepotism. He wanted to make it on his own. I can respect that.
Edit: the first sentence is meant for Kenobi 65.
In the case of Charlie Sheen it sounds to me like he was trying to make a subtle anti-Semitic dig. What a sad, small man!
Either that, or it’s the drugs talking, or the “dry drug” effect if he’s abstaining, and if there is such a thing.
You might have less respect when you consider Cage only wanted to avoid the appearance of nepotism. He apparently was okay accepting the benefits of it however. He took roles in several of his Uncle Francis’ movies early in his career.
Albert Brooks’ real name is Albert Einstein. His brother is Bob Einstein, who played “stuntman” Super Dave Osbourne and Marty on “Curb Your Enthusiasm.”
Moving to the music world, we have:
Chaim Witz - Gene Simmons
Stanley Eisen - Paul Stanley
Edward Mahoney - Eddie Money
Hugh Anthony Cregg III - Huey Lewis
Acting used to be a disreputable profession. No actors were allowed into polite society (except possibly a handful of the elite). Women were considered prostitutes, men grifters or homosexual (back when that wasn’t just a slur but outright illegal). Actors couldn’t stay in most hotels when they traveled, because then decent people would have to mingle with them. Actors changed their names to protect their families from the shame, along with the many other reasons already given.
I also agree that it used to happen much more frequently than now. In the old days, probably 99.9%* of stage names were, well, stage names. Now it’s much lower.
- Not including the children of acting families, who, like the Barrymores, kept their names.
In the past Eliza Dushku would have changed her name. Now it’s OK to have an unusual name.
Engelbert Humperdinck sounds like a real name but it’s not , he’s Arnold George Dorsey.
I think I heard it was because he wanted to stay true to his roots, but the IMDB says he didn’t want to be accused of cashing in on his father’s name. Right now, the decision looks even better because of his brother. 
Martin Sheen took his last name from Archbishop Fulton Sheen.
Who’s this Dorsey character? Some latter-day charlatan, I suppose, trying to capitalize on the name of a famous musician!
Not a bad decision all around!