Le Thanh Hieu/VnExpress/AP Photo

Mark Zuckerberg may be welcome in Vietnam, even if his brainchild Facebook is not.

The Facebook founder is vacationing in the communist country that blocks its citizen from using his social networking site.

According to The Associated Press, Zuckerberg, his longtime girlfriend Priscilla Chan and a group of friends arrived in Vietnam Dec. 22. They spent Christmas Eve in popular tourist spot Ha Long Bay and Christmas Day at an ecolodge in the northern mountain town of Sapa, where Zuckerberg rode a buffalo.

CLICK THROUGH TO SEE MORE PHOTOGRAPHS OF ZUCKERBERG'S VIETNAM VACATION

Vietnamese website Tuoitre News reported that Zuckerberg, 27, and Chan have already spent about $6,000 on travelling by private helicopter.

The pair have been dating since Zuckerberg's sophomore year at Harvard, where they met at a Friday night party for Jewish fraternity Alpha Epsilon Pi. Chan, a Chinese-American from the Boston suburbs. struck up a conversation with Zuckerberg while waiting in line for the bathroom.

"He was this nerdy guy who was just a little bit out there," Chan told the New Yorker last year.

When Zuckerberg left Harvard in 2005 to focus on Facebook full time, he recruited classmates, including Chan, who, according to The Harvard Crimson newspaper, told him, "I'd love a job at facebook," before offering him a Twizzler.

These days, Chan identifies Zuckerberg as her partner on her Facebook page and, according to tech writer Sarah Lacy, she has imposed a set of rules on her steady, including, " One date per week, a minimum of a hundred minutes of alone time, not in his apartment, and definitely not at Facebook."

While the couple seem to be enjoying their vacation, it's likely, given Zuckerberg's insatiable work ethic, that he's finding some time for business, namely expanding Facebook to Vietnam, where social media is growing. Though Facebook is blocked by the government's censors, locals can still access the site with relative ease, but it seems they would rather choose local offering Zing Me.

Zuckerberg, whose net worth is measured in the billions, doesn't need the money. Rather he seems motivated by his obsession to bring Facebook to one billion users worldwide.