And David Duchovny has a masters in English Literature from Yale.
From that link:
Damn, Hedy Lamarr was awesome!
Doesn’t make him a genius, but porn star Ron Jeremy has a master’s degree in Special Education, which (being in special ed myself) I think is quite cool.
I don’t know where this “Celebrity Cowboy” outfit gets its info, but it’s BS. James Woods is not a member of Mensa, nor Quentin Tarantino, Steve Martin, or Sharon Stone. I have no doubt that any of them qualifies, but that is not the same thing as being a member. Geena Davis is a member. You have to either pass the test or send in evidence that you have taken another test that qualifies you, and then pay your fargin’ dues.
Some interesting linkages here: Erdős–Bacon number - Wikipedia
Natalie Portman, mentioned in Gangster Octopus’s link, has published papers on psychology and is, by all accounts, quite smart. No dumb actress she.
Whoopie Goldberg has a PhD in English. Not really “Hollywood,” but the singer from the Offspring has a PhD in physics.
Also, appropo of nothing, I just want to obeserve that in addition to being a math nerd, Danika McKellar also grew up to be smoking hot (just do a Google image search). Smoking hot + math nerd is pretty much an unbeatable combination.
Greg Graffin from Bad Religion has a PhD in zoology.
and Queen Bruin beat me to it.
In my defense I didn’t read the whole thread.
Since we’ve opened up the discussion to include musicians, Jeff ‘Skunk’ Baxter, lead guitarist know for his work with Steely Dan and the Doobie Brothers, is a self-taught expert on missile defense. (From the Wiki article) he has formally served as a U.S. defense consultant and chairs the Congressional Advisory Board on missile defense.
Glenne Headly and Alan Rachins are Mensans. So is Asia Carrera, although I don’t see her listed here:
Robert Vaughn has a PhD in communications from USC.
It’s OK, neither did DtC. 
Cite on the Mensa slam?
Sounds like someone who did not get in. You never said what real world criteria you would use.
Not sure if this qualifies as, but I believe that Alice Cooper is a Juilliard graduate. No small feat in itself.
I haven’t the slightest as to his IQ, but obviously Steven Spielberg is a “Hollywood genius”. To quote Rob Cohen, a Universal executive in the 1970s, “He’s a master at choreographing the elements of the business. He didn’t get to be ‘Steven Spielberg’ just by being a good director.”
He’s likely not what you’re asking, since you’re looking for people with IQ’s above a certain number, but as has been mentioned, there is more to being a true genius than by achieving certain scores on certain tests in favored subjects.
I don’t know if that’s the case, I can’t find any reference to back that up anywhere.
From wikipedia:
Holland was the class valedictorian at Pacifica High School in Garden Grove, California and was a Ph.D. candidate in Molecular Biology from the University of Southern California; however, he abandoned his Ph.D. in favor of focusing on The Offspring. He has a Bachelor’s degree in Biology and a Master’s degree in Molecular Biology, both from the University of Southern California.
Holland is also a licensed Airline Transport Pilot and has made a solo trip around the world in 10 days
A “basic” understanding of science? That seems somewhat at odds with the need to produce a doctoral thesis, no? I mean, unless you’re attending Rubber Stamp U, or bribe the thesis committee or something.
Jodie Foster graduated magna cum laude from Yale, and is fluent in German and French. She has to have some serious brain power.
I don’t know when that entry is dated, but I heard him in a radio interview a couple of years ago saying he’d gone back and finished his PhD.
Besides being one of the most beautiful (and underappreciated) actresses in the industry, Alicia Witt has an IQ of 180. She also has a degree in piano, and once performed professionally.