Under the terms of the agreement with the Australian based company, the Ospreys will wear BLK playing and training kit from the start of the 2014/15 season until the end of 2016/17.
BLK will also supply the regional age-grade teams, as well as providing an extensive range of supporters apparel.
While a relatively new name in northern hemisphere rugby, BLK are a major player in the sports industry.
In Australia they are official kit supplier to Super Rugby teams the Queensland REDS, Western Force and Melbourne Rebels.
In addition, they provide kit to the Fijian and Samoan national teams, as well as leading rugby league and AFL sides.
In the last three months, BLK have confirmed new partnerships with South African Super Rugby side Natal Sharks, and four times European champions Toulouse, with further eye-catching deals to be announced in the coming weeks.
The two organisations share a commitment to achieving excellence, with BLK CEO, Tyron Brant, saying the partnership announcement was a crucial piece in BLK's international
expansion strategy:
"As an organisation we are truly honoured to be entering into a partnership with an organisation which is not only internationally renowned and respected for their achievements on and off the playing field but more importantly because, like the Ospreys, BLK share similar visions for the future.
"We look forward to working closely with the team at the Ospreys, to playing our part through the provision of cutting-edge technologies and innovative apparel for the region's players and administrative team and the teams extremely passionate supporters."
Andrew Hore, Ospreys CEO, echoed Mr Brant's views as he hailed the new partnership as a significant step for the business.
"This is undoubtedly the most significant commercial partnership in the history of the region and is a major statement, both from Ospreys Rugby and BLK" said Hore.
"BLK are a a leading force in the southern hemisphere game, and they have begun making inroads into Europe. We are delighted to be able to confirm our organisation as the latest to commit to a partnership with BLK and are excited about working closely with their team to deliver a product for next season which players and supporters alike will be proud of.
"The Ospreys jersey has reached iconic status in our short but eventful history. We are not even 11 years old as a brand yet our shirt has been the second biggest selling in the UK and Ireland since the 2005/06 season, something we take huge pride in. That statistic alone is a clear indication of the strength of the Ospreys brand and the power of an organisation that continues to lead the way in Wales.
"As a business, we have undergone huge change on and off the field and haven't shirked the difficult decisions. Although there remains uncertainty around the whole of the European game, we are well placed for a sustainable and successful future, thanks to the confidence of market leading businesses like BLK who share out outlook and vision and wish to be a part of what we are doing here. With a number of further positive announcements to come, supporters should share our excitement about the future of Ospreys Rugby."
Travelling to the Liberty Stadium in Swansea for the announcement, Mr Brant said he was keen to develop a range of innovative apparel solutions to assist with individual player and team performance, as well as a range of unique supporter apparel that will be worn with pride by fans right across Ospreylia.
"As a brand we have and continue to evolve and stake our claim as a global leader in sportswear innovation and design, and it's through partnerships like the one being announced with Ospreys Rugby today that we are able to continually go beyond limits known and showcase our advanced technologies in the harshest environments."
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