LuLuLemon Athletica Inc. founder Dennis “Chip” Wilson has agreed to sell half of his shares, about 13.85% of the company’s outstanding shares, for $845 million to private equity firm Advent International. LuLuLemon is No. 112 in the Internet Retailer Top 500 Guide.

In addition to the sale, Advent managing partner David M. Mussafer and managing director Steven J. Collins will be join LuLuLemon’s board of directors, increasing the board from 10 to 12 members. Mussafer also will be appointed co-chairman of the board.

“We welcome the opportunity to work with David and Steven, who have significant specialty retail experience and are deeply familiar with LuLuLemon’s unique culture, having previously served as members of our board,” says Michael Casey, chairman of the LuLuLemon board of directors. “They will bring valuable expertise and important perspective to LuLuLemon. Our board and management team have been consistently focused on enhancing shareholder value and these agreements are important for the company and all of our stakeholders.”

Wilson currently owns 40.2 million shares of LuLuLemon stock, representing 27.7% of the company’s outstanding shares. Once the sale is completed, Wilson and Advent will each own 20.1 million shares. Advent invested in LuLuLemon in 2005 and exited from that original investment in June 2009.

“Advent is a strong partner that knows LuLuLemon and our culture and will be an incredibly helpful addition to the board as we build an even stronger company,” says Chip Wilson, founder and a director of LuLuLemon. “I am delighted with the addition of David and Steven as new directors, both of whom are very familiar with our company and bring significant expertise. LuLuLemon is well positioned to successfully execute on its strategic goals, and I look forward to working alongside the entire board and management team as we focus on leveraging our core values of product and innovation to enhance value for all shareholders.”

LuLuLemon grew its e-commerce sales 33% in fiscal 2013 despite a year marred by a controversy over yoga parents that were overly revealing. The CEO resigned over the controversy.

LuLuLemon did not immediately respond to a request for comment on the sale.