Vicky McClure investigates the tragic trials and tribulations of her great-grandfather, who was interned as a Japanese prisoner of war in Taiwanduring the day World War II.
The actress will follow in her relative's footsteps BBCgenealogy show of 's Who do you think you are?? tomorrow night.
In a segment shared ahead of the program, which airs on Thursday at 9 p.m., Line of duty and the 41-year-old Trigger Point star was openly emotional as she recalled her ancestor Harry Millership's “horrific” experience.
Vicky reflected on her work in the spotlight, saying she has a “very vivid imagination”, adding that she's “struggling with it” as she explores Harry's struggles 6,000 miles from home.
“My mind is all over the place and I'm learning all sorts of horrible things. And it's about my great-grandfather, about my mother's grandfather. It's all too close to home,” she confessed.
Actress Vicky McClure, 41, travels 6,000 miles to Taiwan to learn about her great-grandfather Harry Millership's experiences as a Japanese prisoner of war
Vicky looked visibly tense as she spoke to the camera about her heartbreaking family history.
During the episode she discovered the horrible reality of the journey of Singapore – where Harry's regiment was stationed in 1941 – to the Taiwanese POW camp where he was interned after the Japanese attack on December 8.
Vicky heard that Harry would be locked up in a cramped hold, with hardly any supplies, and that upon arrival at the POW camp he would be forced to work in a copper mine.
To commemorate the 80th anniversary of the D-Day landings earlier this year, the BAFTA Award-winning actor spoke about another family member who served in World War II for an ITV documentary.
Vicky's grandfather Ralph McLure, 97, explained how he narrowly escaped death when his landing craft was hit by enemy fire during the invasion of Normandy.
He was only 17 when he signed up to serve in the Royal Navy and was deployed as a signaller on a landing craft on that historic day.
Vicky shared her respect for her grandfather and stressed the importance of remembering D-Day, saying: 'It's so important to keep this history close and make sure the children know about it.
“It's so important that people like my grandfather can remember that. I'm sure there are many veterans who didn't feel able to or didn't want to remember.
“So any information we can get about that history is important.”
Harry was interned in a Taiwanese POW camp after the Japanese conscripted his regiment in Singapore on December 8, 1941
Vicky, pictured with her grandfather Ralph McClure, a World War II veteran, spoke candidly about the importance of remembering what happened on D-Day in an ITV documentary
Spice Girl Melanie C discovers more about her roots in the new series Who do you think you are?
The Line Of Duty star is just one of many celebrities set to join the upcoming series of Who Do You Think You Are?.
Over the course of its 20-year run, the series has helped Harry Potter author JK Rowling, Strictly Come Dancing's Shirley Ballas and actor Sheridan Smith discover their roots.
The new series stars comedian Paddy McGuinness, athlete Dame Jessica Ennis-Hill and Spice Girl Melanie C.
Liverpool-born Melanie C discovers her family history includes political activism.
She also discovers that her family survived the Great Famine in Ireland.
Other celebrities who have signed up include TOWIE star Gemma Collins, Troublemaker singer Olly Murs and former EastEnders actress Rose Ayling-Ellis.
Executive producer Colette Flight said: 'The celebrities were moved to tears, laughed, were angry and had fun as they learned about the lives of their ancestors.'
Who Do You Think You Are? airs every Thursday at 9pm on BBC One and BBC iPlayer.