Paul Rudd knew his parents were close, he just didn't know how close.
In the upcoming episode of "Finding Your Roots," the PBS series dedicated to celebrity genealogy, host Henry Louis Gates Jr. tells the "Ant-Man" actor that his parents are second cousins.
"Which explains why I have six nipples," Rudd quips.
"Does this make my son also my uncle?" the actor, who was born in Passaic, asks with a half-worried look. The episode, called "Immigrant Nation," airs Tuesday.
The premise of "Finding Your Roots" may be straightforward: deliver personal family histories to celebrities. But the show's discoveries, enabled by genealogical research and DNA testing, have resulted in a constant stream of life-changing surprises, and even controversy.
Returning for its fourth season on Oct. 3, the show delivered a perfect revelation -- that Larry David and Bernie Sanders, linked through "Saturday Night Live" sketches and humorously compared to one another during the 2016 presidential election, are distantly related.
"The whole premise is that we're looking at the book of life over someone's shoulder," Gates tells NJ Advance Media, referring to an actual book presented to each guest that details moments in their family's history. "It makes it more interesting to be looking over the shoulder of a celebrity -- being a voyeur." Another aim, he says, is to deconstruct notions of racial purity.
Paul Rudd in a scene from the PBS series 'Finding Your Roots.' Rudd, a Passaic native, discovers details about his Jewish family's history in England and Eastern Europe.
"We're all related in the history of oppression," says Gates. "Women, Jews, black people." A professor at Harvard University, where he's the director of the Hutchins Center for African and African American Research, Gates has also hosted PBS celebrity genealogy series "African American Lives" and "Faces of America." He says each season starts with a cork board of fantasy A-listers producers would like to get on the show.
"To my enormous amazement, nobody knows anything about their own ancestry," Gates says.
Rudd, born in 1969, got his start in '90s movies like "Clueless" and "Romeo + Juliet," going on to star in film comedies like "Wet Hot American Summer," "Anchorman" and Judd Apatow's "Knocked Up" before becoming a bonafide superhero in Marvel's "Ant-Man." His parents, Gloria and the late Michael Rudd, were born in England.
When Rudd was 10, his family moved to Overland Park, Kansas, since his father was a sales manager for Trans World Airlines in Kansas City.
Rudd, who is an Ashkenazi Jew (a group from Eastern Europe), tells Gates he faced anti-Semitism in Kansas and was called "Jewboy." He would make his own Jewish jokes to diffuse the situation (and prevent himself from getting beat up).
"I certainly feel as if being Jewish is in the marrow of my bones," Rudd, 48, tells Gates. He would've been Paul Rudnitsky if his family name hadn't been changed by his grandfather, another person who was just trying to fit in (and get work).
"I love doing Ashkenazi Jewish ancestry because it's so difficult to do," Gates says. The show, sponsored by Ancestry.com, works with a team in Provo, Utah and hires historians and genealogists abroad to find documents relating to funerals, marriages and baptisms as well as archival photos.
The show found the graves of Rudd's great-grandparents, Samuel and Esther Rudnitsky, in London. Shmuel, Samuel's Hebrew name, led genealogists to a draft certificate that shows he joined the Russian Army in 1895, when he was 20.
"Jew, unmarried, illiterate," Rudd says, reading the certificate. "Wow, what a catch."
The Rudnitskys were born in Kholmich, a shtetl, or Jewish village, in what's now Belarus but was then a poor part of the Russian Empire where Jews suffered. They later moved to London's East End and worked in butcher shops. There, Rudd's grandfather changed his name from Davis Rudnitsky to David Rudd. At the time, there was an anti-Semitic movement brewing in England headed by Oswald Mosley of the British Union of Fascists.
David Rudd served his country during World War II and was stationed in Sicily during the Allied invasion of Italy, but found anti-Semitism raging during a postwar recession when British fascists threatened to bomb synagogues. He left for New York in 1949.
"He had served in World War II to fight fascism, and he comes home to find fascism," Gates tells Rudd, whose parents are related through his great-grand-uncle on his father's side, who was also his great-grandfather on his mother's side. The man had come to England from Russia, where he, too, faced anti-Semitic riots at the turn of the century.
A portion of the show that did not make the cut: Rudd is distantly related to Barbara Walters.
"Jewish people tend to share DNA with pretty much all other Jewish people," says CeCe Moore, the lead DNA genealogist for the show, who Gates calls "the Sherlock Holmes of genetic genealogy."
In addition to the Bernie Sanders-Larry David connection, she previously found that Bill Maher, another celebrity of Jewish ancestry who grew up in River-Vale, has an Irish cousin in Bill O'Reilly. This season, Moore sussed out that Ted Danson is related to Stephen Colbert. In an upcoming episode, thanks to DNA testing, Tea Leoni, whose mother was adopted, discovers a photo of her biological grandmother. It looks so much like her mother that she begins to cry.
"I look at her and I say she didn't die -- she's still alive, in her 90s," Gates says. Cue a family reunion in Louisiana.
A growing group of celebrities have found their ancestors were slave owners. Anderson Cooper learned his fourth great-grandfather was killed by his slave. And after the 2014 Sony email hack exposed that Ben Affleck had asked the show to omit the fact that his ancestor owned slaves (his episode did not include the information), PBS postponed the third season of "Finding Your Roots."
"You're not responsible for what your ancestors did," Gates says. "Guilt is not heritable."
Larry David was flabbergasted to find his relative fought for the Confederacy.
"Oh my goodness, I hope no slaves show up on this," he said before turning the page to find just that. Christopher Walken, meanwhile, learns his uncle was in a German police battalion that shot Jews or rounded them up for transport to extermination camps.
Actor and musician Fred Armisen, who always believed he was a quarter Japanese, learns his grandfather, a dancer in Japan, was not only famous in his home country, but also a Korean man passing as Japanese (and a secret agent who performed for the Nazis).
The Rudd episode features Scarlett Johansson, who discovers she is half Swedish, not Danish as she thought. She tears up as she learns her cousins succumbed to the Holocaust when they were teenagers in the Warsaw ghetto. And John Turturro learns his grandfather's application to retrieve his father from an orphanage was denied because he was married to a black woman.
In the latest episode, "Selma" director Ava DuVernay finds that her ancestor was a white slave owner in Haiti, leading her to suspect a DNA test will show she's mostly European. Reading the results, she throws her hands to the sky and rejoices:
"I'm black!!"
"Finding Your Roots" airs 8 p.m. Tuesdays on PBS. Paul Rudd's episode airs Oct. 31. Previous episodes are available to view on the show's website; pbs.org/weta/finding-your-roots
Amy Kuperinsky may be reached at akuperinsky@njadvancemedia.com. Follow her on Twitter @AmyKup or on Facebook.