It was a great honor for Halong Phoenix Cruiser to welcome Mark Zuckerberg - CEO facebook, his girlfriend Priscilla Chan and other friends to share the joy on Christmas Season in Vietnam

Billionaire Facebook founder Mark Zuckerberg spent the Christmas festivities with his girlfriend... riding a buffalo.

The 27-year-old gingerly climbed onto the horned beast in Vietnam - one of the few countries in the world to block his social network site.

Zuckerberg travelled with his Chinese-American girlfriend Priscilla Chan and a group of friends, flying into Hanoi on December 22.

Feeling bullish: Mark Zuckerberg rides a horned buffalo in the Vietnamese tourist resort of Sapa

Flower girl: Priscilla Chan carries a bouquet given to her by local tourist officials in Ha Long Bay

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They were seen visiting the Hoa Lo Prison Museum, known as the 'Hanoi Hilton' where American prisoners of war were held during the Vietnam War.

From there they were taken by helicopter to the popular tourist destination of Ha Long Bay where they spent the day on a cruise ship and rowed kayaks.

On Christmas Day the group flew to an eco-lodge in the northern mountain tourist hotspot of Sapa.

A local farmer helped control the buffalo as Zuckerberg slowly rode it, but Priscilla kept a low profile as they visited a village.

Communist-controlled Vietnam has largely prevented the country accessing Facebook - angering U.S. government officials who have accused it of limiting freedom of expression.

Boat trip: Zuckerberg and Priscilla , both wearing sunglasses in the centre of the picture, tour Ha Long Bay

Welcome: Local tourist officials greet Zuckerber before he tours Ha Long Bay with his girlfriend and pals

Walkabout: Zuckerberg, centre, walks down as he visits a village in Vietnam's northern Sapa

HE OFFERED HER A JOB AT FACEBOOK... SHE OFFERED HIM SOME CANDY

The couple have been dating since their college days at Harvard after meeting at a party while waiting in a queue for the bathroom.

Chan later told The New Yorker that she thought Zuckerberg was 'this nerdy guy who was just a little bit out there.'

When Zuckerberg left Harvard in 2005 to focus on Facebook full time, he began recruiting classmates.

According to The Harvard Crimson, he was sitting outside after a campus recruiting session when Chan walked by.

When he offtred her a job, she responded by offering him a  a candy Twizzler.

Author and technology writer Sarah Lacy has written that Chan has imposed strict rules on her relationship with Zuckerberg .

One of the top rules: 'One date per week, a minimum of a hundred minutes of alone time, not in his apartment, and definitely not at Facebook.'