The Team Fortress 2 Blog announces that those who have preordered Left 4 Dead 2 at Steam or elsewhere will get a crossover bonus of an in-game version of Bill's hat for Team Fortress 2 (not everybody can pull off the beret, but it looks great on you). Word is:

Is Bill's hat the tenth class? All will be revealed in time, but don't hold your breath. Will you get to wear Bill's hat right now, in TF2? Go ahead and hold your breath—now exhale like a champ, because you're a winner and it's happening.

Even if you haven't pre-ordered yet, it's not too late to get in on this unprecedented hat-wearing, history-making crossover event! Pre-order Left 4 Dead 2 now, and the hat is yours. (Also the game at 10% off.)