"Social Network" star Jesse Eisenberg met Facebook creator Mark Zuckerberg for the first time over the weekend, during his "Saturday Night Live" monologue.  Jesse played Mark in "The Social Network", if you didn’t know.

Jesse was bantering with Andy Samberg, who was doing HIS Mark Zuckerberg impersonation, when the real Mark Zuckerberg joined them onstage.  That's when Samberg said, quote, "Wait . . . have you two not met?  Awkward!"

They didn't actually meet at that moment.  Mark also came out during the final dress rehearsal, so it wasn't a LIVE surprise.

(You can check out the video at NBC's site below.  The real Mark Zuckerberg first appears at the 2:30 mark and comes onstage at the 3:30 mark.)