As noted by Gamermint, a poster from Battlefield 3 reveals that the “Limited Edition” of the game will include the “Back to Karkland” DLC pack.
Although EA itself has yet to officially announce if this is actually true. If it is true, the DLC pack will come at no extra charge when you buy the “Limited Edition” of Battlefield 3.
The DLC pack is reported to include four maps from Battelfield 2, that will all be rendered using the sequel’s new game engine; Frostbyte 2. There will be additional trophies and achievements for gamers to unlock. The DLC pack is to be released a month after the game itself.
The image below look legit but EA has yet to formally announce anything yet.