If you've pre-ordered Halo 3: ODST, or you plan to before its release on 22 September, then you'll be pleased to hear that you're getting a little bonus.
You'll be given a token to unlock Sgt. Johnson as a playable character in the "Firefight" game mode that sees you teaming up with friends as an ODST squad for co-operative clearing of waves of enemies.
As previously reported, Halo 3: ODST is a prequel where you don't play as Master Chief, instead taking on the role of a lone UNSC soldier in the city of New Mombasa. ODST, in case you were wondering, stands for "Orbital Drop Shock Troopers".
Halo 3: ODST costs £40, and will be on sale on 22 September. You can pre-order it now.