UPDATE: Ubisoft has now officially released the trailer, which you can see below.
ORIGINAL STORY: A leaked trailer of Ubisoft's highly anticipated Watch_Dogs has been discovered hours before their pre-E3 media briefing.
The trailer, via Destructoid, unfortunately doesn't contain any gameplay footage of the game which casts players as a vigilante hacker named Aiden Pierce. Watch_Dogs was announced at E3 last year and was one of the biggest surprises of the show. It seems Ubisoft were not quite able to keep things under wraps this time round unless, of course, it was an 'official' leak.
In the trailer, we see someone in a trench coat texting on his phone while cameras pick him out from the crowd. The trailer's narrator, presumably Pierce, comments "give me four seconds and a clear signal. I'll get in and you'll never know. But I want you to know. You're not anonymous."
While the trailer is all rendered it should still give you a taste of what to expect when the game is released later this year for PC, Xbox 360, Xbox One, PS3, PS4 and Wii U. You can see the game's box art here. Ubisoft expects Watch_Dogs to match the performance of the first Assassin's Creed, which sold six million copies.