Ah, Hanukah! Festival of Lights! A time for Jews everywhere to get together in a spirit of peace, give gifts and sing songs. It's also a time for gentiles everywhere to ask questions like "So... what's the deal with Hanukah?" and "How do you spell Chanukah?" and "Why does it keep moving around the calendar like a celebratory hobo?"

These are good questions; deep questions. And who better to ask than Hollywood's Jewish stars! But who's Jewish? It's no shock that certain actors are from the tribe (shalom, Sasha Baron Cohen!), but Zac Efron?

Let's take a look...

Kat Dennings

Born Katherine Litwack, her first major role was on HBO's "Sex and the City" in 2000 where she played a 13-year-old who hires Samantha to do the publicity for her Bat Mitzvah. When asked if she is a practicing Jew, Kat (who broke out in "Nick and Norah") responded that Judaism is an important part of her family history (translation: don't ask her any Jewish trivia).

Zac Efron

Yup. He's a Jew -- or, at least, from Jewish ancestry. This elven-faced heartthrob's last name actually means "lark" in Hebrew. And yet, with all the evidence in, it's still really, really, really hard to believe, right?

James Franco

Jews have a reputation for taking education seriously. The "127 Hours" star has taken this tradition and run with it to insane degrees (pun). In recent years, he's attended UCLA, gotten a master's at Columbia, NYU, Brooklyn College and Warren Wilson College -- and he's now at Yale and the Rhode Island School of Design. But when does he find time to call his mother?

Andrew Garfield

Raised in Surrey, England, this handsome up and comer and soon-to-be Spider-Man gets eight days of gifts as opposed to the one day of presents on Christmas. But, what they don't tell you is that, for most of the eight days, you just get stuff like underwear and socks -- only they're wrapped -- like that's fooling anyone.

Ginnifer Goodwin

As a 13-year-old, the "He's Just Not That Into You" star totally rocked her Bat Mitzvah in her home town of Memphis, TN. She's found even greater critical success as the third wife of a polygamist, Mormon-ish family in the HBO series "Big Love," but still does a mean hora on the weekends.

Joseph Gordon-Levitt

Such a nice, well-groomed, Jewish boy, isn't he? The "50/50" star even took time off from his acting to attend Columbia University because knowledge is... well, just insert here one of a million Jewish sayings about knowledge (hint: they all say it's very important).

Jake and Maggie Gyllenhaal

When said in their entirety, Jacob Benjamin and Margaret Ruth Gyllenhaal's full names sound a lot more Jewish, don't they? Jake's parents threw his Bar Mitzvah party at a homeless shelter to instill him with a sense of gratitude for his privileged lifestyle (that and the shelter had better food than the synagogue caterer -- such dry fish!) It must have stung a bit that Maggie had her Bat Mitzvah at the Four Seasons.

Kate Hudson

Mother Goldie Hawn gave her a Jewish upbringing, along with her stepdad, Kurt Russell. It's fun to imagine Kurt coming in after a long day of kicking ass on set, grabbing the menorah and yelling "Goldie, Kate! Let's light up this sucker!"

Scarlett Johansson

Though famously tight-lipped about her personal life, she did mention that she was able to bond with Woody Allen during the making of "Match Point," saying "We have a lot in common. We're New Yorkers, Jewish." Sure. Guess that makes them have a lot in common. Though aliens would not be able to identify these two people as being from the same species...

Mila Kunis

Mila's grandparents were killed in the holocaust and her family was not allowed to practice Judaism in her native U.S.S.R. But in 1991, the "friends With Benefits" star and her parents were lucky enough to escape the Ukraine and moved to Los Angeles where she quickly found success as a child actor. She is proud of her Judaism, even though she is not very trained in its practice.

Shia LaBeouf

His Jewish mother gave him the name Shia, which is Hebrew for "gift from God." Shia got his last name, LaBeouf, from his Cajun father – it's a misspelling of the French term "the beef." But, if you see him on the street, do not call him "meat gift." Resist the urge.

Gwyneth Paltrow

This beautiful "Contagion" star's great-grandfather, whose surname was "Paltrowicz," was a rabbi in Poland long ago. One wonders if Rabbi Paltrowicz would have been a Coldplay fan. One wonders...

Sarah Jessica Parker

Sarah only had a Jewish father and received no religious training growing up so, for a long while, her Chosen People rating was hovering around the 25 percent mark (not too chosen). But after marrying the Jewish Matthew Broderick, her numbers are up to about 50 percent (under consideration of being chosen). We'll keep you posted.

Joaquin Phoenix

Phoenix had a pretty standard upbringing. He was born to a Jewish mom from The Bronx and a Catholic father from California. They joined the cult The Children of God and roamed around South America for a while before relocating to the more kid-friendly environment of Hollywood. There, they changed their last name to Phoenix to symbolize rebirth. Yes, it's an old Jewish story; one you've probably heard many times before.

Daniel Radcliffe

Yes, there are British Jews. And, apparently, most of them are actors. No one is sure how it happens or where they come from. And they're all handsome.

Nikki Reed

Though her brother had a Bar Mitzvah, the "Twilight" star did not herself go through this rite of passage. And we all saw the results in her film "Thirteen" (which she helped write). If this isn't an argument for a Bat Mitzvah, what is?

Paul Rudd

He's handsome, successful and Bar Mitzvah-ed. The perfect Jewish catch. So of course he's married to a blonde shiksa -- all the good ones are! Rudd's grandparents changed their name from Rudnitzky long ago, which was probably a smart choice.

Winona Ryder

This '90s Hollywood icon was actually born Winona Horowitz and had Jewish grandparents who emigrated from Russia. Jewish stars have a long history of changing their last names either from pressure to seem more "mainstream." Well, OK, it's hardly just the Jewish stars.

Evan Rachel Wood

Wood recently brought home to mom every Jewish parent's ideal fiance: rock-star creep-show Marilyn Manson. But before the gothic Chuppah had even been ordered, the engagement was called off, and Rabbis everywhere breathed a sigh of relief.

(Originally published on Dec. 21, 2011, at 2 p.m. ET)