Video report by ITV Anglia's Malcolm Robertson
It is likely to be the biggest film of the year, with an all-star cast that includes Tom Hardy, Cillian Murphy, Kenneth Branagh and making his acting debut - Harry Styles.
Thursday 13 July in London's Leicester Square, Prince Harry will attend the world premiere of Dunkirk, which recreates the remarkable story of more than 300,000 allied troops being rescued from the beaches there.
Involved in that evacuation was a boat now based in Lowestoft which has a starring role in the film.
Last year Richard Basey was asked if they could use MTB 102 in the film. For years he spent time returning the boat to its former glory.
It would have been a bigger surprise if they hadn't wanted it because she's one of the few boats around that was actually there more or less still doing the same job as she's doing now.
In 1940, MTB 102 was one of the last boats to leave Dunkirk, bringing stranded soldiers back to Britain. Mostly she had been involved in co-ordinating the evacuation effort.
What a bonus when Warner Brothers with a big budget came calling. The 102 Trust would not reveal what it is worth - but certainly enough for them to be prepared to spend two months in the port of Dunkirk while filming took place.
Like all charities we're struggling for money all the time so yes it helps to secure the future for the immediate future and we were very grateful to look after such a wonderful vessel for a good few years yet.
They were pretty much kept in the dark about what role the boat would play in the film.
She is the only surviving royal Royal Naval vessel from that remarkable event in 1940.
We were told by a man in the properties department that 102 features in the last scene of the film, which apparently in the film world is the most important scene. I suppose that is the one you leave the cinema with fresh in your mind.
Dunkirk goes on general release in Britain Friday 21 July.