According to this Icy Veins forum post which contains info that looks pretty much legit and I would not post this if it clearly was not.

http://www.icy-veins.com/forums/topic/25473-diablo-1-and-2-hd-coming-out-soon/

I mean why does that sign havee a picture of Diablo 1 and 2 there at all in todays Blizzcon?