Video report by ITV News Correspondent Paul Davies
Sir Peter Jackson's highly praised WW1 film They Shall Not Grow Old brought the grainy footage of the First World War to a modern audience, by colouring and cleaning it up using digital restoration techniques.
The director had said he hoped bringing the old footage back to life would encourage families to investigate their past.
And for one woman, the film gave her a window into her own family history.
While watching the documentary, Jenny Pateman spotted a man who had a distinctive nose, a feature shared by her brother.
She thought she recognised him as her grandfather - which was then confirmed when she received a text from her brother moments later.
Lt Thomas Frayne was pictured on the front line aged 21 - shortly after he was gassed, and suffered the effects for the rest of his life.
Ms Pateman says she will pass on the story of her war hero grandad to her newly arrived grandson Jack.