It was as close an approximation of a Greek island idyll as is possible in Leicester Square.

There was a fake, white-painted church made of wood, real lemon trees had been planted around it in sacks of earth, and fake pink bougain-villea climbed over trellis arches, all to reflect the setting of the musical Mamma Mia!.

The crowd waved Swedish flags to the Abba music that played incessantly for the London film premiere, although for the most part they had shown restraint in their attire. The same could not be said for the cast. Meryl Streep floated around the church in a cloud of red silk.

Colin Firth, Pierce Brosnan, Stellan Skarsgård and Dominic Cooper arrived like black-suited lotharios stepping out the morning after, still slightly embarrassed by their behaviour. “This film is very much about embarrassment,” Skarsgård told The Times. “It’s about surviving embarrassment in your life. This is the first time I have attempted to sing and dance.”

What did he think about Brosnan’s vocal range. “I was too preoccupied with my own singing,” he said. “We were all pretty scared.”

Firth said that the film had been “by turns delightful and mortifying”. He added: “Once I fully understood the script, which took a while, I did it on the basis that it was going to be fun. Then I got called in and found myself singing in front of Björn (Ulvaeus) and Benny (Andersson). It was sheer terror at that point.”

Firth had sung before, although almost all of his performances had taken place in the shower. “And I have never really sung as myself. When I’m singing Johnny Cash to myself, I’m really doing him.”

Cooper said that he had spent a lot of time pretending not to know any Abba. Then a former girlfriend sent him a VHS tape of himself singing Money, Money, Money, word perfect at the age of 13. “It’s sort of been the back-drop of my life,” he said.

Ulvaeus, who arrived in a sandy tweed-style suit, declined to comment on Brosnan’s singing abilities. Of the women, he thought that “Meryl and Amanda (Seyfried) were the best, although they sang 75 per cent of the stuff”. They were both trained singers. “Of course I can sing,” said Ms Streep. “My first Broadway show was a musical.”

Tom Hanks and Rita Wilson, executive co-producers of the film, arrived last. “I think we were in Greece,” Ms Wilson said, “When I just thought, why not?”

Denise Spence, 43, an office manager from Northern Ireland and veteran of “all the Björn-again concerts”, plans to see the show “in something very subtle”. A fan since the age of nine, she has the final few bars of Thank You for the Music tattooed on her right arm.

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