For the millions watching at home it was an unforgettable moment in British TV history.

In February 1988 on BBC’s That’s Life! a man called Nicholas Winton came face-to-face with some of the 669 Jewish children he had saved from the Nazis prior to World War Two.

A surprise reunion, it brought to light a remarkable story – one which has now been turned into a Hollywood film.

And it is set to star Port Talbot’s Sir Anthony Hopkins as the Holocaust hero dubbed the British Schindler.

Entitled One Life, the movie will tell of how Sir Nicholas, a London stockbroker who was knighted for his humanitarian accomplishments in 2003, helped get young Jewish refugees out of occupied Czechoslovakia in 1938.

Overseeing those rescue efforts, as well as ensuring new homes were found for those displaced, Sir Nicholas worked tirelessly to save hundreds of lives.

However, he was always haunted by the thought of all those he was not able to help and never really talked about his efforts. As a result his tale of heroism would go largely unheard of.

That was until some 50 years later when Sir Nicholas’s wife uncovered a scrapbook in their attic detailing everything her husband had done, including the names of all the children who he had helped escape.

News of his story spread, and Sir Nicholas was later called to appear on an episode of popular Sunday night consumer affairs programme That’s Life!

There, as the cameras rolled, the host Esther Rantzen asked the studio audience: “Does anyone here tonight owe their life to Nicholas Winton?”

It was at that point dozens sitting around the then 77-year-old stood up, revealing themselves to be grown-up versions of those little ones he had rescued, albeit just a small percentage.

Immortalised in recent years on YouTube, the emotional clip has since been viewed tens of millions of times, thereby reintroducing Sir Nicholas to a whole new generation.

And now cinemagoers will soon be able to see his exploits unfold on the big screen, with One Life having its world premiere next month at the Toronto International Film Festival.

It was shot last year in Prague, from where children were transported by rail and a statue of Sir Nicholas was unveiled in 2009.

Margam-born Sir Anthony will play his elderly incarnation while actor and musician Johnny Flynn while play him as a younger man.

Helena Bonham Carter will also appear as Sir Nicholas’s mother, alongside Welsh actor Jonathan Pryce.

The film was adapted from a 2014 book written by Sir Nicholas’s daughter Barbara, entitled If It’s Not Impossible… The Life of Sir Nicholas Winton.

One Life’s Oscar-winning production company See-Saw described the drama as “an inspiring true story” and “a race against time”.

It added that, by appearing on television, Sir Nicholas was finally able make peace with his demons.

“It wasn’t until he was surprised by the survivors on live television that he accepted how, when faced with devastating atrocities, saving even one life is a victory,” it said.

“And the British public got to learn the truth about the hero hidden in their midst.”

Sir Nicholas died in July 2015 aged 106.