Vinod Khosla joins Square’s board of directors

Khosla VenturesMobile payments startup Square on Tuesday said it had added well-known venture capitalist Vinod Khosla to its board of directors.

Khosla runs Khosla Ventures, which invested in Square in the past and recently sought to raise an additional $1 billion in funding.

Square is headed by Twitter co-founder Jack Dorsey and now has a reported valuation of $1 billion. Khosla will add his fundraising and business experience to Square’s already buzzing service.

“Square is thrilled to welcome Vinod to our board,” Dorsey said in a statement. “We have worked closely with Khosla Ventures since our inception and Vinod’s expertise, history and input will be a tremendous asset to our company as we continue to grow.”

Khosla established himself in the past as the co-founder of Sun Microsystems and as a major investor during the first Internet boom. Lately, he has become one of the most prolific investors in the clean energy sector and an investor in forward-thinking tech companies like Xobni and GroupMe.

Square was started in May 2010 and says it now processes more than $3 million in mobile transactions per day. The company’s total investment so far has been $37.5 million, which doesn’t include an undisclosed amount from Visa in April.