Facebook founder and CEO Mark Zuckerberg (28) married his long time love Priscilla Chan in a backyard ceremony on Saturday afternoon at his Palo Alto home.

The wedding was a surprise to guests who thought they were celebrating 27-year-old Chan’s graduation from UCSF Medical School.

Zuckerberg designed a "simple ruby ring" for Chan himself - she did not see it until the wedding. Following the vows, guests dined on food from the couple’s favorite restaurants, Palo Alto Sol and Fuki Sushi.

The couple -- who have been together nine years -- had been planning the ceremony for the past five months. Zuckerberg wore a suit and tie, and Chan wore a $4,700 embroidered Claire Pettibone dress featuring matte sequins and ivory cut-outs with a sheer back.

It's been a busy week for the couple, as Chan graduated on Monday, the same day Zuckerberg turned 28. Four days later, Facebook went public; the move brought Zuckerberg's wealth to an astounding $19 billion.