Valve has announced that they’ll be releasing content for both Left 4 Dead and Left 4 Dead 2, with the second game’s add-on coming in March.

Left 4 Dead 2 will see an add-on called The Passing, which, in one chapter, brings the main characters from the first game to meet up with those in the second.

This information came from Microsoft’s X10 event in San Francisco, when Chet Faliszek also revealed news that Left 4 Dead 1 would see more DLC around a month after this.

The DLC for Left 4 Dead 1 will explain how they get to where they are in The Passing.

The Passing will also bring along another type of Infected, the Fallen Survivor, who will sometimes drop items such as health kits when killed.

Prices will be revealed closer to the time.

Valve, as a bit of fun, have revealed that there have been 28,981,249,043 zombies killed in the first couple of months of release of Left 4 Dead 2, along with some other silly stats.