Lisa Kudrow is not the kind of actress who provokes tears - unless it is from laughter. As the kooky and capricious folk singer Phoebe Bouffay in Friends, she and her five Central Perk pals generated global laughter for 10 years in the most popular sitcom of all time. The joy of the show remains, so it comes as a shock to see one of its stars sobbing on camera for the family she lost at the hands of the Nazis.
"The truth is, it was beyond tears," says Kudrow, who is still affected by the horrific history she unearthed about the murder of her great-grandmother in Belarus while filming the United States version of the BBC genealogy series Who Do You Think You Are?
"I know that everyone who takes part in this series is surprised at how much impact it has on them, but I never imagined how much it would affect me."
Lisa Kudrow was making the film PS I Love You in Ireland four years ago when she saw Who Do You Think You Are? "I watched [the Olympic athlete] Colin Jackson's search and it was riveting," she recalls. "It was without doubt the best thing I had ever seen on TV and, because there was nothing like it in the States, I got a compilation together of the British episodes and took the concept to my business partners."
By November 2008, Kudrow's production company was collaborating with the UK producers to make a US version of the series for NBC, with the 47-year-old actress an obvious and enthusiastic participant.
"I've always tried not to do anything that would attract too much attention," says Kudrow. "I've been careful to keep my private life separate and never use it as a marketing device for a movie or TV show. But this was different. This is a factual investigation and not a gossipy tabloid-style show like so many programmes are today, and I wanted to find out about my family. Not just for me, but for all of them."
Her parents, Dr Lee Kudrow, a migraine specialist, and travel agent Nedra (née Stern) are both of Eastern European descent, but initial research into her mother's background met with too many brick walls. "That was disappointing because my great-grandfather was a furrier who just disappeared one day and naturally we wanted to know what happened," she says in an agitated tone reminiscent of Phoebe. "But the problem with some of the very small villages is that records were destroyed and for the film to work you need substance and, if you are lucky, photos or documents."
For Kudrow, substance came in the shape of a memory - an afternoon spent playing games with her late grandmother, Gertrude Kudrow. "I was only little, so had no qualms asking her whether she missed her parents as I had never seen them and she did not speak of them," says Lisa, "It was only then that she started crying, telling me: 'My mother was killed by Hitler with a knife in her back'."
Her father Lee later explained that news of the murder of Gertrude's family was delivered to them in New York in 1947 by a first cousin, Yuri Barudin who was serving on the Polish ship, Batory. Her father even had a photo of the young man, though the family believed Yuri had subsequently died.
The sorrow of her grandmother and the image of the young sailor took on major significance when Kudrow embarked on her research trip. She travelled to Ilya in Belarus, Gertrude's birthplace and home until 1921, when she left for a "better life" in America - leaving her mother, Mera Mordejovich and other family behind.
"The city of Belarus is an incredibly bleak place, though our director Christopher Bruce, who went there with Natasha Kaplinsky for the BBC series, said it had really improved since his last visit. Who would know?" says the actress. "Ironically my grandmother spoke of the great beauty of her village and I could see that beauty the moment I arrived, but the tragedy that befell the village's Jewish population casts a ghostly silence over the place."
With the help of Tamara Vershitskaya, a local museum curator and an expert on Jewish resistance, Kudrow was given access to town records that confirmed that her great grandmother, Mera, was "killed and burned" with 900 other Jews in Ilya in 1942 by Nazi murder squads. Reading from a translated document describing the victims' selection process and their execution in Ilya's market square, while standing at the exact scene of this crime, Kudrow was at her most distraught. The scene makes for emotional viewing and she says that she was overwhelmed and had to turn away from the camera.
"We were told that the Christian population could hear the cries of those who had not been killed by bullets as they burnt alive," she whispers.
Standing by the commemorative tombstone that marks the mass grave, Kudrow says that all she could think about were the children. "I get so angry when I think about them and their poor parents standing there naked and stripped of their dignity before they were killed. How scared they must have been? These were not people anyone had reason to fear. A Jewish baker? A Jewish farmer? They were just not part of one man's vision of the future."
By her own admission Kudrow has never been religious, so did her newly-discovered history bring her closer to her faith.
"Not really," she says without hesitation. "I have always felt very aware of who I am and strongly identified with this group of people of whom I am part. What hit home for me was being in Poland, where we continued the search for my father's cousin Yuri. In Gdynia I was met by a very nice woman who told me I was staying in a good hotel, adding: 'It is where Mr Hitler stayed'. She was so respectful of him, as though his presence there was a selling point. Suddenly I was in a place where Hitler was a Mr.
"I also met with people who had a Jewish grandparent, but didn't consider themselves Jewish in any way. They kept asking me: 'How Jewish are you exactly?' and when I told them 100 per cent, mother and father, they were shocked. I wasn't sure how much more I could take of that."
After so much sadness, which Lisa admits slightly troubled the US broadcasters who like to offer viewers hope before the commercial break, light relief was provided by the discovery of cousin Yuri, who converted to Catholicism and changed his name to Boleshaw to sound more Polish. Alive and well in Gdynia with grown-up sons and grandchildren, the presence of Lisa Kudrow in their home caused even more excitement than the reunion itself. "A lot of people recognised me in Poland and came over, but no one in Belarus," says Kudrow who has a pathological fear of crowds, adoring or otherwise. This does not impact on her decision to continue making films, many of which are highly-regarded independents such as The Opposite of Sex and Happy Endings for which she won awards that sit neatly beside her Emmy for being Phoebe.
Future offerings include Paper Man with Jeff Daniels, Don Roos's Love and Other Impossible Pursuits and a cameo in her "Friend", Courtney Cox's TV series, Cougar Town. There is also her show, Web Therapy, on the internet in which she plays a psychologist dealing with exasperated patients via a web cam.
"The more interesting the parts the better, but for me the work has to be part-time as I want to be in town with my family," says Kudrow who is more than happy to wax lyrical about her husband of 14 years, French advertising executive Michael Stern.
"He got the Jewish name, but isn't Jewish," she quips, having revealed earlier that Kudrow in Belarussian means "curly hair". "We did however have a Jewish person officiate at our wedding (not a rabbi), and Michael was good enough to stand under a chupah and smash the glass."
The couple have a son, Julian, who is 13. Though aware of his family's history, he was not first in the queue to watch Who Do You Think You Are? "What can I say? He likes action movies," sighs his mum. "You know how it is, the story about the cobbler's son having no shoes. I got so many emails from kids who did see it though and that is very satisfying. I think as Julian grows up he will be more interested."
Having secured the likes of Sarah Jessica Parker, Matthew Broderick and Brooke Shields for the first series, Kudrow is finding it a lot easier to cast the second season.
"Now that people have seen it they are hopeful that they too will have fantastic stories to unearth," she says Lisa with Phoebe-like optimism.