Mark Zuckerberg Married His LOng time girlfriend

Mark Zuckerberg and Priscilla Chan

A day after Mark Zuckerberg took his company, Facebook, public, the CEO updated his relationship status to "married."

Zuckerberg, 28, and his longtime girlfriend Priscilla Chan exchanged vows at a small ceremony in their backyard attended by less than 100 guests in Palo Alto, Calif., on Saturday.

Guests thought they were coming over for a surprise party to celebrate Chan's graduation from UCSF medical school, where on May 14 she received her degree in pediatrics. However, Zuckerberg and Chan had been planning the wedding for more than four months, according to a source authorized by the couple.

Zuckerberg designed Chan's wedding ring, a simple ruby sparkler, himself.