Billie Joe Armstrong performed at Mark Zuckerberg’s wedding

Mark Zuckerberg, who had an intimate, backyard wedding with Priscilla Chan, had at least one famous name on the modest guest list in the form of Green Day’s Billie Joe Armstrong.

The singer performed at the Facebook founder’s Palo Alto, California nuptials on Saturday, People magazine reported.

“They’ve been friends for some time,” a source close to the artist said.

“He wasn’t paid. It was a total impromptu wedding present for a friend,” the source added.

Though newlyweds Zuckerberg, 28, and wife Chan had been planning their nuptials for more than four months, the ceremony came as a shock to friends, who thought they were coming over for a surprise party in celebration of Chan’s UCSF medical school graduation.

The couple, who met while attending Harvard before Zuckerberg — who is now worth more than $19 billion — started Facebook, have been dating for nine years.