Missing it's original release date of late-march, Left 4 Dead 2's "The Passing" DLC will be released sometime next week, according to the the announcement from Valve on the official Left 4 Dead 2 blog.

"The Passing" (560 Microsoft Points, $7), will add a new chapter to the Left 4 Dead story, with the main hook being a crossover between the survivors in the original game and the survivors in the sequel. The DLC also includes new weapons and infected.