Keira Knightley weeps as she hears the wartime love story of her sonar operator grandfather and brave volunteer grandmother.
The Hollywood star is also moved to tears when she learns her great uncle Andrew, an RAF bombardier, was shot down over Germany and spent 18 months as a prisoner of war.
The revelations, in Channel 4 documentary My Grandparents’ War, come as the actress recalls that tough grandma Jan, from Glasgow, never spoke about her experience.
In 1943 she and the rest of the family had feared that Andrew Williams, Jan’s younger brother, was dead. He was reported missing in action after being shot down during his eighth bombing raid over the industrial town of Essen.
In fact, though the pilot perished, the rest of the crew had ejected and spent 18 months in a prison camp.
As the war neared its conclusion, they were made to walk 600miles in freezing conditions – over two months – before members of the US Army delivered the news the war was over.
Andrew later wrote of the moment he realised he had survived it: “I remember staggering to a wall, sliding down to the ground and crying.”
Reading out his words, Keira adds: “We’d finally been released.
“I was only about seven stone by this time and I’d thought we were all going to die.”
When she hears how her great gran came running down the road to greet the taxi as he finally made it home, Keira gasps: “I bet she did. Oh God, it gets you, doesn’t it?”
From Atonement to The Imitation Game, the mum of two has appeared in many films set during the Second World War but never knew what her own family had experienced.
As her roots in Scotland and Wales are revealed, she laughs: “I’ve made a career out of playing posh English. Suddenly it’s – oh no! It’s all fake. She’s pretending.”
In the documentary, a historian tells Keira that her grandad Joseph “Mac” MacDonald, originally from Cardiff, served in the Royal Navy for 12 years from 1934.
He was a sonar operator, listening for U-boats. He was on HMS Wolverine when it helped rescue 700 Irish Guards from the stricken MS Chrobry in under 20 minutes, all while under intense attack.
Hearing what they went through, Keira marvels: “It’s no wonder they didn’t talk when they got back.”
Jan had joined the war effort by volunteering as a clerk, working 200 miles away from home at a military hospital in the western Highlands.
She was later involved with organising troop movements “of a secret nature” and is described as having carried out “errorless” work which would have involved helping the US Army prepare for the D-Day landings.
Keira says: “She was part of the unseen workforce. They came from very ordinary backgrounds... very ordinary people were asked to do extraordinary things. And they did.”
Keira learns that her grandad, courting her grandma in Glasgow, crawled on his belly during a Blitz air raid to get to a date with her.
Keira laughs: “I mean, she was terrifying. This was the generation of youth that were constantly exposed to violence and the prospect of death.”
Remembering glamorous Jan, who died when the actress was 11, Keira said: “She was only 5ft 1in but she was there in a big way.”
At the end of the film she cries as she reads out a sweet love poem from Mac, who died four years before she was born. Keira, 37, says: “It must have meant so much. It’s really got me. It’s moving because it’s so small.”
Her own mother Sharman reveals to Keira: “He loved her to bits and pieces all her life, he really did, and gloried in her voice, in her excess, in her flamboyance.”
- My Grandparents’ War, Thursday, Channel 4, 9pm.
