A chance encounter between a fan and a music festival booker has led to Waipu teen-metal band Alien Weaponry scoring a slot on stage at one of Europe's biggest music festivals.

The band - made up of 17-year-old drummer Henry de Jong, his brother Lewis, aged 15 and bass player Ethan Trembath, also 15 - will perform at the Bosko Bursac stage at MetalDays in Slovenia, which runs from July 23-28.

The Bosko Bursac stage is one of two main stages, and the festival is listed among the top in Europe by authorities such as NME and LiveLifeExtreme.com.

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Believed to be the youngest act to perform at MetalDays, as well as the first New Zealanders, the connection was made when a fan approached festival booker Crt Batagelj at an airport in Athens and showed him a YouTube video of Alien Weaponry's single, Ru Ana Te Whenua, manager Neil de Jong said.

''After watching more music videos and a short documentary, Crt immediately got in touch with the band, offering them a slot on MetalDays "whenever you are ready to come to Europe", Mr de Jong said.

The offer prompted the band's NZ management to seek further opportunities in Europe, resulting in a three-year contract with Berlin-based management agency Das Maschine, who have secured several additional festival engagements to be announced over the coming months.

Adding more shows to the tour made it a real possibility, as the income from performance fees will help cover the costs of the band living in Europe for several months.

However, the three teenagers still had the problem of getting there – until Creative New Zealand came on board, approving a grant of $19,000 to cover travel, insurance and transporting instruments.

"We were all still at school this year, and there's no way we could have raised that much money ourselves," Ethan said.

"So we are incredibly grateful to Creative New Zealand for helping us."

The trio set a goal to play at a number of big European festivals before they were out of their teens, so it's a dream come true that it's happening two years ahead of schedule.

"It's hard to believe that come the middle of next year we'll be sharing the stage with some of the biggest metal names in the world," Henry said.

The brothers are direct descendants of Te Ahoaho (a warrior who died in the battle at Pukehinahina, Gate Pa); and several of their songs are sung in te reo.