Wedding Invitation Mystery

So with March brings in the wedding season! I love weddings and cannot wait for some of our close friends to tie the knot. We have quite a few invitations on our ribbon board right now. But never before have I gotten an invitation from someone I have never met. 

We received one in the mail from a couple that neither of us knew! We consulted our parents thinking that they gave our address out to a family friend and we just didn't know their kids, siblings etc... But alas, our parents didn't know them either.

So on to the Facebook stalking! Neither of us are friends with either the bride or the groom. No mutual friends with the bride and only 2 mutual friends between the two of us with the groom. And yet, we cannot find an answer as to how we know the lovely couple. For some reason I find this hilarious and I REALLY want to know when we met them. Because the invitation is definitely addressed to Preston and I, and was sent to our apartment. I am stumped...

Xoxo