THERE will be plenty of happy faces when the new musical Sunshine On Leith hits cinema screens this weekend.
One person who won't be smiling, however, is the gentleman who landed a part as an extra, as a man staggering out of a pub following a knees-up.
His scenes have been cut and the director, Dexter Fletcher, stepped in instead.
"It's not there for a, 'Hey, look at me!' moment," insists 47-year-old Fletcher. "It's there because the guy we got didn't do a great job, so I was encouraged by our cameraman and cast to do it. If people know it's me and smile, that's great, but I'm slightly dubious about it."
His is not the only cameo in the feel-good film. Identical Scottish twins Craig and Charlie Reid, better known as The Proclaimers, also crop up.
"They were on set two times and I just said, 'Guys, will you walk out of the pub here?'," says Fletcher. "It gives us a great light-hearted moment, and you know you're allowed to laugh in this film."
In fact, the duo's songs feature throughout the narrative and are, to all intents and purposes, the reason the film came about.
Sunshine On Leith started life as a stage production. Well, more accurately, the title first belonged to a Proclaimers album from 1988. Then, in 2005, screenwriter Stephen Greenhorn was looking for a Scottish musical he could develop with his friend James Brining, artistic director of the Dundee Repertory Theatre.
One night, while listening to The Proclaimers, he drunkenly scribbled "Proclaimers musical" on the back of an envelope and went to bed. He woke up with no recollection of his idea – until he saw the scrawl.
After securing permission from the Reid brothers, Greenhorn and Brining spent two years developing the show before its stage premiere in 2007.
"A film producer had seen the show and thought it'd be a great idea for a film," says Fletcher. "I got involved a little bit after that. It's a companion piece, rather than an adaptation."
It's little surprise the movie's being dubbed "MacMamma Mia". Fletcher, who as an actor has starred in the likes of Press Gang, Band Of Brothers and Hotel Babylon, and made his directorial debut with 2011's Wild Bill, has no problem with the association.
"That's no bad thing. It did fairly well," he jokes, referring to the global smash hit Mamma Mia. "This might be set in Scotland, and there aren't any Abba songs, but I think that's a natural comparison."
When DNA Films, the same production company behind hits like 28 Days Later and The Last King Of Scotland, approached Fletcher, they thought an outsider's perspective would bring added texture – he hadn't even seen the stage show. But he "read all the reviews and saw, obviously, how brilliant it was", he adds.
"I was relieved I hadn't seen it, because it meant I didn't know how tough an act I had to follow," he says, laughing.
"Musicals were my first great love as a kid. The first film I remember sitting down to watch was Singing In The Rain, and of course, I was in Bugsy Malone."
Indeed, a schoolboy Fletcher made his film acting debut as Baby Face in the 1976 hit. When it came to Sunshine On Leith, like Bugsy's director Alan Parker he was keen to ensure the story would work dramatically with or without songs.
In the same way Mamma Mia bears no resemblance to the lives of the four members of Abba, Sunshine On Leith doesn't focus on Scottish twin singers.
Instead, the story explores the Henshaw family who live in Leith, just outside Edinburgh, and their relationships with assorted friends and partners.
At the head of the family are husband and wife Jean and Rab, played by Jane Horrocks and Peter Mullan, while relative newcomers Freya Mavor and George Mackay play their kids, and Kevin Guthrie and Fletcher's former Misfits co-star Antonia Thomas are the siblings' respective boyfriend and girlfriend.
"As we had Jane and Peter, it gave us a bit more freedom with the younger cast. We could use undiscovered, newer talent, which is always an exciting opportunity to have."