Talented Liverpool duo Adam Cafferty and Michael Bourke, who make up the events band Acoustic Odds, were starting out on the stag do of long-time friend Jimi Murphy at Cellar Bar, next to the train station.
Spotting a piano, the pair launched into a stirring rendition of The Waterboys' 'The Whole Of The Moon', stunning regulars.
"We were doing the ale trail, so we hopped off the train, wandered into the pub and there was a piano there winking at me.
"I said to Mike, 'come on, hop on that and let's have a play'. It was just a bit of fun."
The video, filmed by the stag himself, quickly went viral on social media, with England goalkeeping hero Jordan Pickford, X Factor star Olly Murs, Radio One DJ Chris Stark re-tweeting it on Twitter, as well as Mike Scott, The Waterboys frontman himself.
Across Twitter and Facebook the video has received millions of views.
Stag Jimi said he was amazed by the reception it has received.
He said: "They're incredible, two of my very best mates and they're so talented. We've all been overwhelmed by how it's gone down and the lads are over the moon!
"They're playing at my wedding in Greece next month which will be a bit special for us."
Adam and Mike played two further songs before continuing the famous 'Ale Trail', a cult-favourite bar crawl stretching from Batley to Stalybridge, by hopping on the train to Dewsbury.
Adam said: "It was a good laugh. When we started there were just a few people but the pub started filling up as we went on.
"We wished there was a piano in every bar we went into!"
Acoustic Odds can be found on Twitter.