Altair costume an unlockable in MGS4

Snake will also have access to an iPod on which he can listen to collected music.

According to a GameSpot report on the recent Metal Gear Solid 4 wrap party, the April Fool's MGS4 video which featured Altair is actually real. The star of Assassin's Creed will be an unlockable character model - exactly how he is unlocked remains a mystery.

There's more bizarre stuff in the game too. Snake will have access to an iPod in-game, enabling him to listen to music he collects. GameSpot reports that additional tracks will be offered as DLC. The game will also feature a lot of product placement, including Triumph motorbikes, Sony Ericsson mobiles and real-life clothing items.

Metal Gear Solid 4 is scheduled for release worldwide on June 12, exclusively for PS3.