Anthony Mackie (The Hurt Locker) and Dominic Cooper (An Education) are in talks to join Benjamin Walker in Abraham Lincoln: Vampire Hunter.  Deadline reports that Mackie is up for the role of Will, Lincoln's best friend.  I bet they have great discussions about slavery while they're in the middle of killing vamps.  As for Cooper, Variety reports that he's negotiating for the role of Henry, "a mythic, ageless figure who turns Lincoln into an axe-throwing expert slayer of vampires".  Last week, we reported that Joaquin Phoenix was the front-runner for Henry, but it looks like he's passed on the part.Director Timur Bekmambetov (Wanted) is clearly going for rising stars in his casting and that's a smart move since it keeps costs down but by the time the film opens next summer, Mackie and Cooper could be better known.  Hit the jump for more on the two new additions and a brief synopsis.  Abraham Lincoln: Vampire Hunter is due out in 3D on June 22, 2012.Mackie will be seen next month in theaters in The Adjustment Bureau and again this fall in Shawn Levy's Real Steel.  He's also attached to star in the heist thriller Man on a Ledge.  As for Cooper, he drew rave reviews at Sundance for his dual performances in The Devil's Double.  He'll next be seen playing the young Howard Stark in Captain America: The First Avenger and in the drama My Week with Marilyn.Here's the synopsis of Seth Grahame-Smith's novel, Abraham Lincoln: Vampire Hunter:

Indiana, 1818. Moonlight falls through the dense woods that surround a one-room cabin, where a nine-year-old Abraham Lincoln kneels at his suffering mother’s bedside. She’s been stricken with something the old-timers call “Milk Sickness.”

“My baby boy…” she whispers before dying.

Only later will the grieving Abe learn that his mother’s fatal affliction was actually the work of a vampire.

When the truth becomes known to young Lincoln, he writes in his journal, “henceforth my life shall be one of rigorous study and devotion. I shall become a master of mind and body. And this mastery shall have but one purpose…” Gifted with his legendary height, strength, and skill with an ax, Abe sets out on a path of vengeance that will lead him all the way to the White House.

While Abraham Lincoln is widely lauded for saving a Union and freeing millions of slaves, his valiant fight against the forces of the undead has remained in the shadows for hundreds of years. That is, until Seth Grahame-Smith stumbled upon The Secret Journal of Abraham Lincoln, and became the first living person to lay eyes on it in more than 140 years.

Using the journal as his guide and writing in the grand biographical style of Doris Kearns Goodwin and David McCullough, Seth has reconstructed the true life story of our greatest president for the first time-all while revealing the hidden history behind the Civil War and uncovering the role vampires played in the birth, growth, and near-death of our nation. [Amazon]