A rumour coming straight out of the Official Xbox Magazine suggests that gamers will be able to download and rock out to the Halo Mjolnir Theme Song, which greets you when you fire up Halo 2.
The opening guitar in the theme was recorded by seven-string guitar virtuoso Steve Vai. We've put in a few calls to the right people but they couldn't help us either way.
But seeing as though a Spartan featured as an unlockable character in Dead or Alive 4, we reckon there's every chance of this happening. We officially want Guitar Hero II on Xbox 360 even more than ever.