Mark Zuckerberg Marries Priscilla Chan in Surprise Ceremony

May 20, 2012— -- Newly minted billionaire Mark Zuckerberg had an important status update Saturday evening: Married.

The 28-year-old tied the knot with his longtime girlfriend, the recently graduated Dr. Priscilla Chen in a private ceremony at the couple's home in Palo Alto, Calif.

"With all the news that Facebook had been taking up this week, this is the one that no one expected. On the heels of the second largest IPO in history, the CEO gets married," said Joe Brown, editor for tech blog Gizmodo.

Zuckerberg took off his trademark hoodie and donned a suit for the small ceremony held in his backyard.

Fewer than 100 people attended. Guests all thought they were there to celebrate Chan's graduation from medical school.

The couple had been planning the ceremony for four or five months, according to a guest authorized to speak on behalf of the couple.

Zuckerberg designed a simple ruby wedding ring and Chan had not seen it before the ceremony, the guest said.

The wedding feast came from the couple's favorite Palo Alto restaurants, Palo Alto Sol and Fuki Sushi, and for desert they had Burdick Chocolate "mice," which Chan and Zuckerberg had on their first date.

The couple met at Harvard and had dated for nine years before tying the knot.

Chan's experiences from medical school inspired a new initiative on Facebook to foster organ donations.

"She's going to be a pediatrician so our dinner conversations are often about facebook and kids and the kids that she's meeting. She'll see them getting sicker and then all of a sudden an organ becomes available and she comes home and her face is all lit up because someone's life is going to better because of this," Zuckerberg told ABC News' Robin Roberts.

The Facebook founder's wealth soared to $19 billion when he took his company public on Friday.