Green Day are set to play to tens of thousands of fans in Brisbane tomorrow when the Soundwave 2014 headliners close the opening date of the festival with a 3-hour set.

But last night, the US pop punk veterans played to a few hundred very lucky Sydney-siders in a surprise warm-up gig.

The trio caused a social media storm last night when they tweeted details of a free pub gig, at Sydney’s Captain Cook Hotel, less than an hour before it was due to start. Despite the late-notice, it didn’t take long for fans looking to catch Green Day performing in a rare, intimate setting to flood the Paddington hotel.

According to one lucky fan quoted in The Australian, frontman Billie Joe Armstrong arrived on stage to a sea of heaving bodies and announced, “I guess a few of you saw the tweet.”

Along with bassist Mike Dirnt, drummer Tré Cool, and touring guitarist Jason White – Green Day whipped through an hour-long set cherry-picking from their near-25-year-strong discography.

The band also took requests from the moshing, crowdsurfing crowd of some 200 for a 12-song setlist, which included requisite arena-filling anthems ‘Jesus of Suburbia’ and ‘American Idiot’ – as a montage clip uploaded by the band to their official Facebook revealed today.

Darren Wood, owner of The Captain Cook Hotel, tells The Australian that the plan for the warm-up show coming together on the day of the show, but that keeping mum on a surprise gig from one of the world’s biggest US acts was no mean feat.

“We got a call today and had to keep it on the down low,” said Mr Wood, who co-ordinated the one-of-a-kind gig with Inferno Music instrument-supplier boss Tim Davy and Ray Lalotoa, of the My Sydney Riot blog.

“It happened in all of about five minutes. Green Day came and checked it out and said ‘this is going to work, we’re 99 per cent going to play’, and just said ‘don’t tell anyone about it’,” says Wood.

Davy added: “These things don’t happen everyday.”

They certainly don’t – which is exactly why social media understandably lit up after the show with fans tweeting of their lucky experience while others gloated with their photos and videos from the show.

View more footage and the setlist for the Captain Cook Hotel gig below.