Having been leaked recently, today Microsoft is officially announcing its NASCAR expansion for Forza Motorsport 6 on the Xbox One. The new expansion will add 24 new race cars to the mix as well as a brand new location in the form of the Miami Homestead circuit.

The expansion adds a new World Tour career mode to Forza 6 which Microsoft says is good for 10 hours of additional racing. It's described as the ultimate "what if," pitting America's finest stock cars against other elite racers from across the globe.

The new location, Miami Homestead, will be available to play in all modes of the game and will also include new NASCAR themed leagues and rival events. The cars come from a variety of teams including Team Penske, Hendrick Motorsports, Stewart-Haas Racing, Joe Gibbs Racing and Chip Ganassi Racing.

The NASCAR expansion also adds a couple of new mechanics to Forza 6 for the first time. There's now a rolling start as well as a more complex drafting system, essential for NASCAR success.

"The NASCAR Expansion highlights the power and passion of both 'Forza Motorsport' and NASCAR," said Dan Greenawalt, creative director for Turn 10 Studios. "With the addition of the NASCAR Expansion, 'Forza 6' now offers more than 600 Forzavista™ cars to collect, customize, and race. Players will be able to compete on tracks from around the world and across a huge variety of international motorsport disciplines. Bringing these kinds of automotive fantasies to life is what Forza Motorsport is all about."

The expansion pack will cost $20 and is set to be available starting today. Find out more over at ForzaMotorsport.net