Call of Duty Black Ops Secret Stage: JFK, Nixon and Castro Battle Zombies

Wondering who the unlockable players are in the new "Call of Duty: Black Ops" game? Wonder no more.

Warning: spoilers below.

JFK, Nixon, Castro, and McNamara - zombie killers.

Yes, it's true. At least it's true in the latest installment of "Call of Duty: Black Ops."

After finishing the single player mode, a special "Zombie Mode" of the game is unlocked.

You're summoned to a secret Pentagon meeting featuring President John F. Kennedy, President Richard Nixon, Defense Secretary Robert McNamara, and Cuban President Fidel Castro.

During this top-secret meeting, zombies breach the Pentagon and threaten the lives of the famous foursome.

The meeting room is conveniently equipped with an arsenal of fully-loaded guns - ready to spill some zombie blood.

President Kennedy delivers a few lines of inspirational dialogue and then mayhem ensues.

The game play is simple: kill zombies and stay alive. 

Whenever you feel overwhelmed by the zombie hoards, be sure to keep an ear out for JFK and Nixon as they deliver funny one-liners of encouragement.

In the regular "Zombie Mode," the premise is simple - you and three of your friends are stuck in abandoned building and millions of zombies want to eat your brains for a midnight snack.

Your objective: survive long enough in the low-lit environment by decapitating zombies.

While it will look familiar to gamers that played "Call of Duty: World at War" - this year, Treyarch the developer added the historical quartet to add to the fun.

Last year, "Call of Duty: Modern Warfare 2" sold over 22 million copies worldwide.