Costas and Burton originally struck up a correspondence in 2003, but it has taken over five years for their planned collaboration to bear fruit, during which time Burton has become an in-demand producer and genuine pop star as one half of Gnarls Barkley. Costas, meanwhile, has performed under several different monikers but has remained true to her love of bucolic folk.

The Last Laugh could easily have been a flippant mess. Instead, it has a beguiling charm that grows with each listen as the songs reveal their hidden depths. It helps that the contributing musicians include the likes of Scott Spillane (Neutral Milk Hotel) and Italian composer Daniele Luppi.

This is a spacey album that allows the music room to breathe and accentuates the whimsical quality of Costas's lyrics. Her songwriting bears close similarities to Vashti Bunyan, heavy on the hippy imagery and rooted in fantastical tales of knights and talking animals. This may turn some people off but with the freak folk movement in full flow at the moment there is little here that truly jars.

The true genius of The Last Laugh lie in the musical kaleidoscope of sounds that Burton and string arranger Luppi use to frame Costas's twee ramblings. The standout track Go Walking initially sounds like a lost classic from the Sandy Denny-era Fairport Convention. After several plays the gorgeous melody, Luppi's lush strings, and Burton's discreet electronics indicate that the players are not content to rest on tradition, infusing the basic folk rock structure with a playfulness that roots this music firmly in the twenty-first century.

Burton feels utterly at home within this environment, and it is interesting that The Last Laugh is a greater showcase of his production nous than more vaunted collaborations with The Black Keys and Beck.

The freewheeling structure of a track such as Lucid gives Burton an almost limitless scope to layer his samples, beats and synths, although he is skilled enough to leave Costas's airy vocals as the central instrument. Occasionally his influence is more pronounced, notably on the eerie bass rumble that drives JD Folk Blues, the swooshing sound effects on the deliciously named Under The Influence Of Jaffa Cakes, and the cod reggae of Jelly Belly.

The more you listen to The Last Laugh the more you realise that this is a match made in heaven. Without Danger Mouse's involvement this would be yet another freak folk album to file alongside the latest from Devendra Banhart, but equally you can't imagine Burton succeeding with any other artist from this most esoteric of genres.

The marriage of old and new may be the defining characteristic of Burton's production worldview, but few expected him to journey into the folk world. It is to Costas and Burton's credit that they have fashioned such an enchanting album from such an unpromising premise. The Last Laugh may be one of the year's curios but jaded music fans should check it out with undue haste.