UK fitness apparel brand Gymshark has entered a strategic partnership with equity firm General Atlantic in a deal that values the business at more than GBP1bn (US$1.3bn).

The deal sees General Atlantic take a 21% stake in the business and Melis Kahya Akar, head of consumer for EMEA at General Atlantic, take a seat on the board. The partnership is designed to facilitate further growth and international expansion, specifically into North America, where Gymshark has already established its largest customer base.

In conjunction with General Atlantic's investment, founder Ben Francis is increasing his stake in the company to over 70%. Francis set the brand up in 2012 from his parent's garage. It was recently recognised as the private company with the fastest-growing profits in the UK, with latest revenues over GBP250m.

"It has been an incredible ride over the last eight years to get to this point, but today signals the next chapter in the Gymshark story. We are nothing without our community, so we will use this new investment partnership to get even closer to them on a truly global scale," said Francis.

"I firmly believe Gymshark has the potential to be to the UK what Nike is to the US and Adidas is to Germany, and today is a significant step to realising that."

Gabriel Caillaux, co-president, managing director and head of General Atlantic's business in EMEA, added: "We believe Gymshark is an authentic, disruptive and differentiated brand. Against a backdrop of rising social media usage, rapid growth of e-commerce and increasing focus on health and wellness, Gymshark is positioned to seize the opportunity of further growth."