DICE have revealed that the upcoming Vietnam DLC for Battlefield Bad Company 2 will actually ship with five maps, rather than the previously promised four. The catch however, is that the new map won't be unlocked until players have completed 69 million in-game achievements.

The Battlefield Blog explains that the map is Operation Hastings, which players of the original Battlefield: Vietnam should recognise as a remake from the 2004 title.

If you didn’t play it back then, it’s one of the favorites among our fans, featuring everything awesome in one fantastic arena: boats, helicopters, tanks, jeeps, temples, and the signature bridge dividing the map into two strategic areas.

Don't fret too much about that dauntingly high achievement number however though, as it's a group effort spread right across all platforms (unlike BF 1943's 43 million kills goal which was platform specific).

You and all your friends playing on PS3, PC, or Xbox 360 need to perform 69 million team actions across Battlefield: Bad Company 2 and Battlefield: Bad Company 2 Vietnam. So what’s a team action? Well, it’s any and all of these: resupply, revive, heal, spot, and repair. We start counting on December 21st, so make sure you contribute from the start!

The Operation Hastings map is previewed in a new trailer today and certainly makes the game look pretty damn fun. Watch it right here on AusGamers.

Battlefield Bad Company 2: Vietnam is due on PC (via both EA Store and Steam) on December 18 2010 (19th here in Aus), with Xbox 360 and PS3 offerings due to follow on December 21 and 22 respectively.