Metal Gear Solid's Raiden will appear as a playable skin in Assassin's Creed Brotherhood.
Joystiq sources say the Raiden "outfit" is unlocked by completing all tasks in the Animus' new "virtual training" mode.
You might remember being able to unlock Altair's robes from Assassin's Creed in Metal Gear Solid 4. You had to complete the game with 50+ knife kills, 50+ CQC grabs and trip less than 25 alerts.
Ubisoft announced free PS3-exclusive DLC for AC: Brotherhood yesterday.
The game's out on November 19 in the UK.