Bethesda has said Operation: Anchorage will be available for Fallout 3 from 27th January.
This, the first of three chunky DLC packs, will cost 800 Microsoft Points (GBP 6.80 / EUR 9.60) from Xbox Live Marketplace and Games for Windows Live.
There's no extra content for PS3 owners, sadly, due to an exclusivity agreement with Microsoft.
The date arrives as Bethesda releases a long-awaited patch addressing numerous bugs in all three versions of the post apocalyptic role-playing game.
Operation: Anchorage adds a military simulation mission that whisks players back to a very different pre-nuclear wasteland world where Chinese invaders need repelling. Adventurers will fit into a tightly run special ops team and have to survive within the rules of the training program. We'd rather fit into tight Spandex, but beggars can't be choosers.
There's around five hours of content on offer, plus a new perk and plenty of unique items and weapons to collect.
Operation: Anchorage will be followed by The Pitt in February and Broken Steel in March. The former adds an industrial raider town to investigate, while the latter recruits players into the Brotherhood of Steel and bumps the level cap up to 30. Broken Steel can be played after finishing the main Fallout 3 campaign.