The good folk tasked with transferring 'Mamma Mia' from stage to screen had two gigantic advantages.
Firstly the small matter of the soundtrack -- effectively the run of Abba's entire back catalogue, and secondly the use of the storyline -- a compotent if unremarkable tale of a bride-to-be inviting her three potential fathers to her wedding on a beautiful Greek island.
What could possibly go wrong?
Well there's the music. Benny and Bjorn penned some of the most glorious songs in the history of popular music. But they also had the huge advantage of having Agnetha and Frida's awesome pipes to sing them. So the film-makers needed to be damn sure they roped in some major vocal talent.
And for the first ten minutes or so, it looked very much that they had. The delightful rendition of 'Honey Honey' by the three girls set the scene beautifully, all fun and frolics on a tropical island, and I began to have high hopes.
But within minutes the wheels began to come off.
It would appear that the producers had the choice of big voices or big names. Sadly they opted for the latter.
Pierce Brosnan and Colin Firth may be great eye-candy for the ladies, but can they sing?
Well put it this way, your dad singing at your cousin's wedding probably wouldn't be any worse. Brosnan's mauling of 'SOS' was a horror to behold, and Firth's rendition of 'Our Last Summer' hovered precariously on the precipice of disaster.
Likewise, Meryl Streep, otherwise a fine actress, frequently floundered in the vocal department. 'The Winner Takes It All', the ultimate test for any Abba tribute, resembled nothing more than a train wreck but I confess to a misty eye during 'Slipping Through My Fingers', a song which has an unexpected poignancy now that I'm a parent.
The young girl playing Sophie positively shone on the rare occasions when she was allowed to burst into song, but the main focus bewilderingly appeared to be on the A-listers cringe-worthy karaoke.
It wasn't all awful -- Julie Walters rescued 'Take A Chance On Me' through her sheer manic joie-de-vivre and 'Money Money Money' held a certain charm, but for large sections of the film, it was embaressing hide behind the sofa time.
Which is a real shame because the narrative, the location and the awesome songs (many of which sound better today than in the 70s) are all present and correct. They just need someone to sing them.
Having said all that, if you can check-in your cringe-meter at the door, 'Mamma Mia' is a harmless and enjoyable piece of cinematic fluff.
Personally I'm now tempted to go and see the stage show for comparison, but I suspect I'm more likely to just give my 'Abba Gold' CD a whirl instead.