Eidos is to release exclusive Tomb Raider: Underworld content for the Xbox 360, amounting to around six hours of extra material in two distinct chapters.
The first chapter, Beneath the Ashes, will be available over Xbox Live Marketplace this Christmas, with the second chapter, Lara's Shadow, due early 2009.
"We’re thrilled that Xbox owners will be able to extend their Lara Croft adventures with exclusive Tomb Raider: Underworld episodes," commented George Peckham, general manager of global third party publishing for Microsoft.
"We look forward to continue working closely with our great publishing partners to deliver the most robust gaming experiences, only on Xbox 360."
Tomb Raider: Underworld isn't the only high-profile title with exclusive downloadable content for the Xbox 360. New content for Rockstar's Grand Theft Auto IV is expected on the console before the end of the year.
Tomb Raider: Underworld will also be released on PlayStation 3, PlayStation 2, PC, Wii and DS.