Who Do You Think You Are? BBC1, Monday at 9pm
DANIEL Radcliffe admits he knows very little about his ancestry.
Armed with a photo album and a piece of paper with a family tree scribbled down by Granny Pat before he was even born, the actor begins his quest to find out more about his background.
Best known for starring in the world famous Harry Potter series, Radcliffe is the latest celebrity to get the genealogy show’s treatment, following in the footsteps of Danny Dyer and Boy George.
Now in its 16th series, there appears to be no sign that viewers are getting tired of the format.
This episode begins with the actor revealing he can’t even remember his great-grandfather’s name.
"I want to say Phil, but that’s not right," he says.
"This is very embarrassing."
He looks back at his own childhood, growing up in west London, telling how his family is a "very tight-knit kind of unit" particularly after he was catapulted to fame, aged just 11.
Radcliffe - whose family descends from Russian and German immigrants - first meets Louis Gershon, a descendant of his great great grandparents, who fills in a few blank spaces on their shared family history.
He produces a photograph of Radcliffe's great-great-grandfather, who bears a strong resemblance to the actor.
His great-great-grandfather Louis had emigrated from Germany to South Africa in the late 1800s after diamonds were discovered there. He later settled in London, running a successful diamond business in Hatton Garden, which he passed onto his son Samuel.
But as the family tree unravels, it's the actions of Samuel that makes for dramatic storytelling.
Radcliffe's great-grandfather Samuel was embroiled in bankruptcy following a potentially fraudulent heist at his jewellery business.
Anti-Semitic police didn’t believe the Jewish trader and accused him of faking it for an insurance pay out. He became the focus of intense publicity and tragically took his own life.
And this is where Radcliffe is seen at his most emotional as he reads aloud the suicide note Samuel left for his wife Raie.
"I cannot face bankruptcy after 22 years of trading so am taking the coward's way out, but I can assure you my angel to leave a girl like you is more than a wrench, I worship and adore you," wrote Samuel.
Tearfully Radcliffe says he wishes he could reach back in time to comfort his great-grandfather.
Crying at the content of the note, he said: "It's sad to think of it getting so bad for him that he had to do this".
Radcliffe also learns about the First World War experiences of his great-great uncle on his father's side, who hailed from Co Down.
In a trip to Banbridge, Radcliffe uncovers four of his great-great-uncles fought in World War One, including one named Ernie McDowell.
He visits his Aunt Linda who produces a bundle of letters written by and to Ernie, which had been kept by his great-grandmother.
Amongst them are some love letters sent to Ernie by someone called Jeannie.
"We will get them all a good day when we are getting married, won't we love?" one letter reads.
Another reveals Ernie's injuries during the war, including being shot and contracting frostbite, before Radcliffe discovers he was killed by artillery, leaving behind a wife.
He is upset by their story of love being destroyed, but relieved they were "able to be a young couple for a little while".
The actor fills in a lot of gaps in his family's history in the episode and was taken on a particularly emotional journey.
But he's not negative about what he discovered, he looks to the positive.
"I can’t be sad about it because everyone was loved, and ultimately that means that, even if their time on Earth ended prematurely and sadly, it was worth having," he said.
