Facebook co-founder Sean Parker has donated $100,000 (£62,000) to support the US state of California's ballot measure to legalise marijuana.
Financial filings for the Proposition 19 campaign revealed the donation.
Facebook co-founder Dustin Moskovitz also made donations totalling $70,000 to the measure last month. The pair are no longer with Facebook.
Californians vote next month on whether to legalise the possession and sale of marijuana.
"What's interesting here is that [Parker] is a member of the generation that really gets it," Drug Policy Alliance spokesman Stephen Gutwillig told the Associated Press news agency.
"We think he's pivotal to the future of drug policy reform in the country," said Mr Gutwillig, whose organization will be the main beneficiary of Mr Parker's donation.
Mr Parker, who was recently portrayed in the film The Social Network, joined Facebook in 2004 and helped steer the website's first major round of funding as the company's first president.
The internet entrepreneur, who is now a partner at a Silicon Valley venture capital firm, also worked as the co-founder of the music sharing service Napster at the age of 19.