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Kent Eanes, NBC
Retired NFL running back Emmitt Smith learns about his family.

Lisa Kudrow discovered that doing genealogy and family history can be an emotional journey.

She knew that members of her family had been murdered by the Nazis during World War II. But going to Belarus for the new NBC series "Who Do You Think You Are?" made that real.

"It's being there and walking the same path that these people walked to their death that doesn't allow you to keep it at an emotional distance like I was always comfortable with before," Kudrow said in a teleconference with TV critics.

"There's a deeper impact with it. And then also knowing that as hard as it was, knowing that the story's going to reach a lot of people. … And the intimate details of these stories give personalized history the impact it's supposed to give."

Kudrow, the former "Friends" star, is not only the subject of one of the episodes of "Who Do You Think You Are?" but one of the executive producers. She was captivated by the original British version of the show.

"I fell in love with the show," she said. "I thought it was fantastic and wanted to know why we don't get to have that in the U.S."

The seven-episode series, which premieres Friday at 7 p.m. on Ch. 5, takes seven celebrities on very personal, yet highly relatable journeys. In addition to Kudrow, episodes feature Sarah Jessica Parker, Emmitt Smith, Matthew Broderick, Brooke Shields, Susan Sarandon and Spike Lee.

But while the family histories belong to celebrities, the histories are almost entirely about the people next door.

"While the person who's taking the audience on this journey is well-known, their great-great-grandfather was not famous," Kudrow said.

"Most of their parents weren't," said executive producer Dan Bucatinsky. "I mean, we go back one parent, and they're regular folks."

But that doesn't mean dull. Parker discovers she had ancestors caught in the middle of the Salem witch trials. Smith and Lee each find both slaves and slave-owners. Broderick learns of heroes in both World War I and the Civil War.

Shields discovers Italian and French nobility on one side, working class tragedy on the other. Sarandon solves a family mystery.

The British creator of the show, Alex Graham, told Kudrow it might not be that easy. He "kept saying well let's just be aware that … 30 percent of the time, these stories are a dead end because there are no records, or it's just 500 years of sheep herders so there's no story to present.

"And the shock and surprise was almost every single person that we did preliminary research on gave a great story."

While "Who Do You Think You Are?" falls into the category of reality TV, it's about as far from the kind of exploitation program as it can be. Each episode is essentially a minidocumentary.

"That was one of the key factors for me — how about some good quality TV that's entertaining and enriching?" Kudrow said. "Because I do think it's really enriching.

"(The series) is a big deal in the U.K., so I don't know why it shouldn't be here. Because every family has a story. So everyone watching will find every episode relatable on some level."

And there's an element of American history in each episode. Larger historical events put in the context of personal stories.

"Every single person comes from some kind of struggle, somewhere," Bucatinsky said. "You dig back a generation or two and, whether you are first generation or second generation, your roots are Latin America and there's a lot of Latinos in this country. And Asian Americans. I just hope that over time, we get to sort of dip into all of them because all of them sort of are uniquely American stories like I think our first seven (episodes) are."

"The show itself isn't really about names and dates as much as it's about the stories that accompany the names and dates," Kudrow said.

Not only are the stories engrossing in and of themselves, but they seem certain to spark interest in genealogy among viewers.

"Almost everyone who's seen the show has tried to find out more about their family tree. They just log onto Ancestry.com and immediately start looking things up," Kudrow said.

Utah-based Ancestry.com is rather prominently mentioned in most of the episodes. Each hour also features professional genealogists who have done research into the celebrity's family.

And every episode has highly emotional moments when the celebrities make unexpected discoveries about their ancestors.

"There's a moment of this kind of wish fulfillment in every one of them that's … I'm going too far, but it's almost like supernatural to me," Kudrow said.

"Yes, there's something in every story where you can't quite believe it," Bucatinsky said.

Much of Kudrow's episode is hard for her — details of her great-grandmother's death at the hands of the Nazis are horrific. And she admits she had trepidation about delving into the family history.

"I was afraid just to explore the massacre of my great-grandmother and her friends and neighbors and other children," she said. "I mean, I was afraid to go there. … Once I got there, it wasn't fear anymore, it was just profound sadness and rage. And the rage surprised me."

But even her journey takes a surprisingly happy turn. And she certainly has no regrets.

"I can't say that there's anything I learned that I would have rather not learned. That's not part of it at all because I think all information is good, and I think there's still more to learn, by the way," Kudrow said. "If anything, it's inspired me to look for other things to see what else I can find out.

"That's what's sort of fun — it's an investigation. Genealogy is an investigation, and it's fun and intriguing, and you see what you're going to find out."

If you watch …

What: "Who Do You Think You Are?"

When: Fridays, 7 p.m. (debuts March 5)

Channel: NBC/Ch. 5