Earlier this week, we brought you the news when Canadian actor Brendan Meyer (Mr. Young, This Means War) joined the cast of the long-awaited big screen adaptation of Orson Scott Card‘s Hugo and Nebula Award-winning sci-fi novel Ender’s Game, as Stilson, Ender’s classmate who taunts him during ground school.

Now, Variety reports that Harrison Ford (Cowboys & Aliens) and Abigail Breslin (New Year’s Eve) have officially joined the cast of the Gavin Hood directed adaptation. Ford is set to portray Colonel Hyram Graff, who oversees the military facility where gifted youngsters are trained to prevent an imminent alien attack, and Breslin will portray Valentine Wiggin, the older sister to Ender (Asa Butterfield).

About Ender’s Game:

Set in Earth’s future, the novel presents an imperiled humankind who have barely survived two conflicts with the Formics (an insectoid alien race also known as the “Buggers”). In preparation for an anticipated third invasion, an international fleet maintains a school to find and train future fleet commanders. The world’s most talented children, including the novel’s protagonist, Ender Wiggin, are taken at a very young age to a training center known as the Battle School. There, teachers train them in the arts of war through increasingly difficult games including ones undertaken in zero gravity in the Battle Room where Ender’s tactical genius is revealed.

Ender’s Game is slated to hit theaters on March 15th, 2013.