The upcoming big screen adaptation of "Ender's Game" already has its Ender in pint-sized "Hugo" star Asa Butterfield, but now two new stars are circling the project to play two more key roles.

Action icon Harrison Ford and "True Grit" scene-stealer Hailee Steinfeld are both in talks to appear in the film, based on the first book in the beloved science fiction book series by Orson Scott Card

In "Ender's Game," a group of children (led by hyper-intelligent Ender) attend a futuristic military academy where they compete in sophisticated war games with surprising results. According to Variety, Steinfeld would play Petra Arkanian, one of the academy's few female students and a close friend of Ender's.

Meanwhile, Ford would play one of the book's few adult roles, as Colonel Hyrum Graff, who takes the lead in training the kids.

"Ender's Game" is to be adapted and directed by Gavin Hood ("X-Men Origins: Wolverine"). Summit Entertainment is aiming for a March 13, 2013 release.

Ford's "Cowboys & Aliens" flopped this summer, but his work in genre films from "Star Wars" and beyond make him an ideal actor for the material.

After being nominated for an Oscar for her work in the Coen Brothers' "True Grit," Steinfeld was one of the most prominent candidates to play Katniss in "Hunger Games," a role that went to Jennifer Lawrence. She'll soon be seen in in "Forgotten" and "Romeo and Juliet."