It can’t have escaped anyone’s attention that Gears of War 3 launched last week (see our review here) and Microsoft have been quick to announce that the Xbox 360 exclusive sold more than three million copies worldwide in its first week on sale.

In just one week Gears 3 has  grossed more than any 2011 video game to date and, in addition to topping this year’s sales charts, the Gears of War franchise joins the elite ranks of only a select few game franchises to surpass one billion dollars in lifetime sales. Taking the milestone even further, Gears now stands as the first Xbox 360 exclusive franchise introduced this console generation to eclipse the billion dollar milestone.

Gears of War was the first killer app for Xbox 360, and the series has continued to contribute directly to the overall success of the platform ever since,” said Microsoft Corporate Vice President Phil Spencer. “Gears of War 3 kicked off the biggest Christmas period in Xbox history, setting the standard for the kind of amazing, action-packed experiences gamers should expect on Xbox 360 this year.”