Writer Jon Ronson (The Men Who Stare At Goats) draws on his experience as keyboard player for off-the-wall Mancunian frontman Frank Sidebottom in this bittersweet comedy. Michael Fassbender plays the eccentric Frank, a mentally ill loner who constantly hides behind an expressionless papier-mache mask at all times. Lending support are Maggie Gyllenhaal as a bitchy fellow band-member while Ronson's part is played by Domhnall Gleeson, who provides the wry commentary on Frank's descent into despair.
The original Frank Sidebottom was a surreal comedy persona created by the late Manchester musician Chris Sievey, taking the form of an aspiring pop star from the small town of Timperley.
Cheerfully optimistic and oblivious of his own shortcomings, the cult artist counted Caroline Aherne's Mrs Merton among his colleagues and was driven to gigs in the north-west by none other than celebrity DJ Chris Evans.
Writer Jon Ronson (who briefly played keyboards for Sidebottom's band) and Dublin director Lenny Abrahamson (Adam & Paul, Garage) have reworked Sievey's creation into the leader of an avant garde American indie band touring Britain.
However, his key USP remains - the bizarre, oversized papier-mache head that he seemingly never removed...even when in the shower.
During a misfiring tour of Britain, the band's keyboard player attempts to drown himself on a south coast beach and frustrated wannabe musician Jon (Gleeson) - who happens to be passing - is recruited alongside short-fused theramin player Clara (Gyllenhaal).
The band repairs to Ireland to record an album where the psychological quirks of their masked leader (convincingly played by Fassbender) become all too apparent - he favours DIY instruments and 'invents' a new musical scale - yet Jon misinterprets his unquestionable talent as the by-product of a grim upbringing.
It's while attending an American music festival that the real Frank is revealed if not unmasked - he's a troubled genius in the mould of Pink Floyd's Syd Barrett or the Beach Boys' Brian Wilson.
His descent into debilitating depression sinks the band's hopes of success...and sees the comedy recede and the poignancy of his story emerge.
Subtle and wryly amusing, this is a sympathetic glimpse into the ever-musing mind of an off-kilter genius...but how much it's an accurate reflection of the real Chris Sievey (who died of cancer in 2010) it's difficult to say.