BIIRD had never played together when they stepped on stage in Trafalgar Square to face 10,000 people on St Patrick's Day 2024.
Eleven Irish traditional musicians stood side-by-side in elaborate costumes, some meeting for the first time only hours before the performance.
Two years later, the all-female supergroup has sold out venues across the UK and Ireland, toured stadiums with Ed Sheeran, and built a global following - all without releasing a debut record.
Their rise has been rapid, driven almost entirely by the strength of their live performances and word of mouth.
For singer and flautist Miadhachlughain O'Donnell, from County Down, the scale of what the group are now doing would have seemed unimaginable during that first performance.
"It was mental, to be honest," she said. "It was done in the blink of an eye… I don't think we had another gig for a couple of months, I didn't really know where it was going to go from there."
While BIIRD's direction of flight may have been uncertain to its members at first, founder Lisa Canny had been quietly developing the "Spice Girls of trad" concept for about a decade.
"Our main objective, other than making beautiful music, is to change the image around women in trad and folk," Canny said.
"There are these incredible shows that tour the world like Riverdance and Celtic Woman and Lord of the Dance, but the representation of women in these groups is still very much outdated."
A seven-time, All Ireland harp and banjo champion from County Mayo, Canny has long held the reputation of being "the baddie of trad", according to BIIRD fiddle player and harpist Sal Heneghan.
"I think there's never been anything like this done in trad before… With the all-female, and the grungy look as well," she said.
"She's always been known to break the rules and go for different types of stuff."
Idea in mind, the group was not created through auditions or strategic casting. Instead it emerged from a web of relationships Canny had formed in the traditional music world, with many of the musicians already aware of each other's work.
The group's scale, however, wasn't necessarily part of the original plan, with the group alternating between eight and 11 musicians, depending on the production.
"Yeah, it's a big show," admitted concertina player Zoran Donohoe from County Cavan.
"The way she handpicked all of us, it kind of just got to 11 and she was like, 'well, we're going to have to go with this now'.
"We were all just so unique and so different and all had our own things going on. And she was like, 'there needs to be a stage and a place for all of these women'."
If the band's size is striking, so too is its aesthetic. BIIRD works with Irish designers and stylists, championing sustainable, theatrical clothing from the likes of Simone Rocha, Paul Costelloe and Sara O'Neill.
Corsets, glitter, heavy eyeliner and dark tones mark a striking departure from the traditional image of an Irish folk musician, and it hasn't gone unnoticed.
"Our first photo shoot kind of - I'm not going to say broke the internet - but everyone in the trad world was like, 'what the hell is going on here?'" Donohoe recalled.
"We were all a bit shocked, we were wearing stuff that we would never wear… but now we're used to it and we love dressing up, it's like putting on a costume every day."
O'Donnell added that the revamped look brought a learning curve when it came to performing in more restrictive outfits: "I'm used to wearing trackies, so that was an experience."
And although their styling feels modern, the musicians are keen to stress they're not reinventing the wheel - BIIRD's sound remains rooted in Irish tradition, albeit with a contemporary twist.
Their songs weave in Irish lilting, set against a lively mix of drums, fiddles, flutes, harps, banjos, cello and concertina - skills honed over years of playing house parties, pub céilís and traditional festivals.
"There's a lot to be said for the small, intimate gigs," Heneghan said. "They can really get the crowd going, they respond really well and you can kind of connect more."
It was in this environment that they first crossed paths with Ed Sheeran, who joined them for an impromptu session in a County Wexford pub during last year's Fleadh Cheoil na hÉireann.
"It was just instantly he was like, 'you guys are great, come on tour, what do you need? … It was amazing," Donohoe said.
True to his word, the Galway Girl hitmaker has thrown his weight behind the band, bringing them on as opening acts alongside fellow Irish artists Beoga, Amble and Aaron Rowe on his ongoing Loop tour.
Speaking to BBC News NI in April, weeks after their stadium shows in Australia and New Zealand, O'Donnell said it's been a thrill to take their music to the southern hemisphere "where there's so many Irish people".
Among them, Heneghan, who relocated to Sydney last September and was struck by the amount of people that already knew about the band.
"When they heard that we were coming over and gigging, it was just incredible the feedback we all got, it was great craic," she said.
After a run of high-profile stadium performances, and some of their own UK and Ireland headline shows, BIIRD are due to re-join Sheeran in the US later this year.
In the meantime, they have been working on their debut album at the renowned Decoy Studios in Melton, England.
Expected to include a number of Canny's original compositions, the record is coming together nicely, according to Donohoe.
"It works very well, we're very used to being around each other and playing music together and just if there's any issues saying it to each other." she said.
And while the group continues to ride the whirlwind of touring and a newfound sisterhood, O'Donnell said she hopes they are laying the groundwork for something more enduring.
"I think people have definitely been inspired to pick up music and learn songs - younger girls, especially, when they see women in that space," she said.
"In years to come, there may be other BIIRDs that fill our space... Hopefully it lives on past our time."
