It’s hard to believe it’s been less than five short years since the gorgeous, lilting harmonies of Johanna and Klara Söderberg, better known as First Aid Kit, first wormed their way into our ears via their cover of Fleet Foxes’ ‘Tiger Mountain Peasant Song’.

Since going viral on YouTube, this lo-fi interpretation has racked up 3.5 million views, attracting global attention, including that of fellow Swede Karin Dreijer Andersson (of The Knife) who promptly signed the sisters to her Rabid Records label. The two have barely looked back since.

Fast forward to present day and First Aid Kit have two critically acclaimed albums under their belt, a legion of followers across the globe and are in the midst of their third tour of Australia, which unsurprisingly is a sell-out.

Fraser A. Gorman and Big Harvest open the show to a rapidly filling room with ‘Take Me To My Grave’ from last year’s debut EP.

Gorman’s performance is typically amiable, the songs are enduring and his crisp raillery peppers the breaks as he takes the time to introduce each song, often replete with ambling narrative history. The highlights are largely in the newer material, suggesting a bright future for the talented young songsmith.

Big Harvest prove a crack complement to Gorman, with violinist Sophia Lubczenko a standout on vocal harmonies and lead on their cover of The Band’s ‘The Weight’.  Similarly, Eagle & The Worm’s Jarrad Brown on upright bass provides some much-appreciated texture to the set.

First Aid Kit, in five-piece tour mode, stepped on stage to rapturous applause from the crowd, which appeared to completely eschew any stylistic or age designation, offering further evidence of the seemingly universal appeal of the band.

Opening with ‘In The Morning’, from 2009’s The Big Black And The Blue, was a masterstroke, allowing the full force of the sisters’ intertwining voices to wash across The Forum’s Corinthian-faux-splendour, beginning and ending the song with their ethereal pitch-perfect a capella.

‘Blue’, the third single from 2012’s The Lion’s Roar followed, bringing with it the first of few signs that the performance could have benefitted from a more articulate backing band, with Johanna left to play both bass and vibraphone parts on her keyboard, in turn sacrificing elements the delicate interplay between vibes and guitar which underpins the studio version.

The sisters’ rapidly maturing voices, along with their faultless confidence and puckish antics again make it hard to believe only five-and a-bit years have passed since they first began writing and performing together.

Dedicating songs to Richard Dawkins and Pussy Riot (‘Hard Believer’ and ‘Our Own Pretty Ways’ respectively), alongside their native Swedish ‘tack så mycket’ (thank you) and Eurovision-inspired vintage costumes only served to further endear them to the already infatuated crowd.

If that wasn’t enough, their rendition of ‘Ghost Town’, sung off-mic and accompanied only by Klara’s unamplified acoustic guitar at front of stage, had the crowd singing along faintly, as not to drown out the delicate sound emanating from stage.

The remainder of the set was lifted from the breadth of their catalogue, ably highlighting the remarkable versatility of their voices; particularly that of Johanna – who, whilst largely confined to harmonising – displayed a deep and complex timbre not immediately apparent in their recorded output.

The only flat moment came during ‘The Lion’s Roar’, as the lack of additional instrumentation left the rendition a shade subdued.

Fans were treated to two covers during the encore bracket, Simon & Garfunkel’s ‘America’ and ABBA’s ‘Chiquitita’, both fair and fitting choices. The former due to the sisters’ unwavering adulation of the music of the United States, and their identification with the music of Gram Parsons, Bright Eyes and Paul Simon; the latter in clear homage to one of their country’s most successful musical exports.

The band capped off the evening with a rousing version of ‘King Of The World’, replete with headbanging from Johanna, and a baleful guitar swagger from Klara in an elegant display of tongue-in-cheek, rock n’ roll star mimicry.

With two tours of the country under their belt in less than a year, it appears that Australia has well and truly embraced First Aid Kit, and with performances like this evening’s, it’s easy to understand why.

View the photo gallery of First Aid Kit’s show at The Forum here.