SAN FRANCISCO — Facebook CEO Mark Zuckerberg is speaking out publicly for the first time in favor of immigration reform.

The 29-year-old billionaire spoke Monday night in San Francisco at the debut screening of "Documented," a documentary by activist and journalist Jose Antonio Vargas.

Zuckerberg said he's advocating for comprehensive immigration reform because it's "really important for the future of our country and for us to do what's right." He says it's not just about securing more visas for engineers at Facebook and other Silicon Valley companies.

Zuckerberg and his former Harvard University roommate Joe Green recently founded the organization to advocate for a pathway to citizenship for nearly 11 million immigrants living in the U.S. illegally.

But Monday was the first time Zuckerberg has spoken publicly in support of immigration reform.