Blizzard announces the Goblins vs Gnomes expansion Hearthstone will be released on December 8th, adding plans for online launch parties in a later update. Here's word:

Since the announcement of Goblins vs Gnomes at BlizzCon 2014, we’ve been tinkering away in preparation to bring one of Warcraft’s greatest rivalries to Hearthstone. Today we’re excited to announce that Hearthstone’s very first expansion will be exploding onto game boards starting December 8!

Goblins vs Gnomes adds over 120 new cards to craft, win, or purchase, all featuring the manic mayhem of Azeroth’s most mischievous machinists meeting mind to mind, mech to mech, and tech to tech.

We’ve already explored some of the themes that you’ll encounter when rumbling tracks, whirring cogs, and roaring rockets propel the new cards into your collections:

Goblins vs Gnomes cards can be purchased as packs, crafted with dust, or earned in the Arena. Goblins vs Gnomes card packs will work just like the classic card packs that you already know, but they’ll have an explosive new wrapper, and contain all new cards!