By Mark Savage
Entertainment reporter, BBC News
When director Paul Weiland turned 50, the leading lights of the British film industry turned out for his birthday party.
Fourteen-year-old Gregg Sulkin plays Weiland's character
Among the 250 guests at his 45-acre Wiltshire mansion were people like Richard Curtis, Anthony Minghella, Helena Bonham Carter and Rowan Atkinson.
But, far from enjoying the preparations for the big night, Weiland had been losing sleep over his after-dinner speech.
"I'd been to a lot of very grown-up 50th birthday parties where people like Sebastian Faulks were giving these most eloquent speeches," he says.
"I thought to myself: 'What am I going to bloody say?'"
Weiland says he became "preoccupied" with the speech, racking his brains for anecdotes about his life and marriage which could entertain an audience with the highest expectations.
"And then I just had this thought," he says, "that the last big party I'd had, no-one really showed up to - because it was my Bar Mitzvah, and it was on the day of the  World Cup final.
"And the speech went down so well that, afterwards, there were quite a few producers in the audience and they came up to me and said: 'We should make that as a movie.'"
Inspired by the reaction to his speech, Weiland wrote a script outline with one of his closest friends - who just happened to be Richard Curtis.
It was instantly picked up by Working Title, the British company behind Curtis's hit films Four Weddings and a Funeral and Notting Hill, and shooting took place last year.
Sixty Six stars Gregg Sulkin as the young Weiland - although in the film he is renamed Bernie Reuben.
Sulkin, 14, was one of 5,000 boys who auditioned for the role, but he says he only went along "as a bit of fun" after his cousin had suggested it.
The young actor appears in almost every scene, and manages to hold his own against established stars like Bonham Carter, who plays his mother, Esther.
Comedian Catherine Tate also makes an appearance in the film
He admits he was nervous about sharing the screen with the Oscar-nominated actress.
"I thought, because she's a big actress, she wouldn't take much notice of me," he says, "but it was completely the opposite.
"And there weren't many nerves because I didn't really think about what would happen if it went wrong; I just thought: 'Let's enjoy every minute of it.'"
If he was enjoying himself, Sulkin gets very little chance to show it during the film.
His character obsessively plans for his Bar Mitzvah, putting together seating plans and menus, but his dreams are increasingly downscaled as his family faces financial difficulties.
Then he discovers that his ceremony clashes with the World Cup final - and if England get through, none of his guests will turn up.
Many of the film's comedic highlights come from Sulkin's attempts to put a curse on Alf Ramsey's team as they progress through the tournament.
Ironically, for an actor who spends his debut film praying for England's defeat in the World Cup, Sulkin is a footballer in the making.
Helena Bonham Carter takes on the role of Weiland's mother, Esther
"I played for Queen's Park Rangers for four years and then West Ham [United] for two," he says. "And I'm with Tottenham now - playing right-back."
Weiland's film briefly put Sulkin's football career on hold - the young star was not able to play during the shoot in case of injury.
"That was probably the hardest part for me," he admits.
But Sixty Six is not just a story about a Bar Mitzvah, it also portrays the difficulties faced by working class families during a period more commonly associated with the Beatles and Carnaby Street.
In the role of Weiland's obsessive-compulsive father, Manny, Eddie Marsan turns in a touching performance as a man trapped by his own misfortune.
Bonham Carter is equally powerful as his wife, who has to hold the family together as her husband withdraws into himself.
Weiland admits that the film helped him to deal with the demons of his childhood.
He even brought in real wallpaper, furniture and fittings from his parents' house in order to make the movie more realistic.
"Sometimes people were worried about my sanity [because] I wanted all this stuff around me," says the director.
"In a way it was because I used to feel so uncomfortable going back to my real home.
"I thought: 'Get it out of there, put it on a set, control it, use it and it's gone.'
"And now I've done it, it's over with and I'm looking for something else to be neurotic about."