Washington, May 20 (IANS): Topping a very busy week after the launch of a flotation at the US stock exchange, Facebook co-founder and chief executive officer Mark Zuckerberg upgraded his relationship status. He and longtime girlfriend Priscilla Chan have tied the knot.

"Mark Zuckerberg added a life event to May 19, 2012 on his timeline: Married Priscilla Chan," the 28-year-old Zuckerberg announced on his timeline on the social network.

The 27-year-old Chan and Zuckerberg met at Harvard and were dating for more than nine years. Chan is an American-Chinese, Xinhua reported.

A photo posted on Facebook showed the young CEO wearing a suit jacket at the wedding rather than his trademark hoodie, while Chan wore a sleeveless white wedding dress with lace.

The couple tied the knot at Zuckerberg's home in Palo Alto, California.

The guests at the wedding believed they were going to celebrate Chan's graduation, but found they were at a wedding instead.

The wedding ring, a "very simple ruby", was designed by Zuckerberg, BBC reported.

"Zuckerberg's wedding was in his backyard, before fewer than 100 guests, who thought they were there to celebrate Chan's graduation," according to a tweet from a Huffington Post editor.

The wedding wrapped up a busy week for the couple. Zuckerberg turned 28 Monday, the same day Chan graduated from the medical school at the University of California, San Francisco.

On Friday, he rang the bell at New York's Nasdaq from the Facebook headquarters in California, staging one of the most anticipated initial public offering in Wall Street history.

Facebook's valuation after its flotation means the social network is worth about the same as internet shopping giant Amazon, and more than the value of Disney.

Zuckerberg continues to control around 56 percent of the voting power of the company.