San Diego Comic-Con 2013 is in full swing, and the cast of "Ender's Game" sat down with MTV to speak about the film.

Cast members Asa Butterfield (Ender Wiggin) and Hailee Steinfeld (Petra Arkanian) did not hold back, talking about their first reactions to the film, how true the movie stays to the book, and what they nerded out to when they were younger.

"Wow, this is going to look incredible," Butterfield said, referring to his first viewing of artist renditions of the costumes and sets.

With epic, enormous set designs, the pair had to prepare for the action of the novel. Butterfield said the cast had to go through a ton of training in boot camp, learning how to march, salute, and cadences of military life.

However, most fans are concerned about how true the film stays to the book. In the novel, Ender ages from a 6-year-old to 12-year-old preteen, but that wouldn't necessarily make sense for the film.

"When I first read the book, I knew they would have to age up the characters," Butterfield said.

Butterfield pointed out as with any film adaptations, there are changes in the film.  He assured fans they would enjoy the movie, saying it is "as truthful as it can be, being in a different medium."

Steinfeld, who plays the character Petra, said she referred to the book to prepare herself for the role, calling the novel "an extra 200 pages of insight." She believes Petra and Ender had a great connection in the film because they shared similar struggles.

"There's a real truthful connection, sort of being outcasts in a way...they're out in a situation where they don't know who to trust," Steinfeld said. "...Petra and Ender have each other."

After the teen actors brief interview, Harrison Ford sat in the hot seat. Though the film has big sets, amazing green screen effects, Ford believes the most important part of Ender's Game is that it deals with issues that are current in society today.

"The moral issues involved are very important things to think about," Ford said.  "...It's the kind of movie that people like to get out of the house and see on the big screen."

According to the "Star Wars" actor, once you start to look into the digital effects in a move, you lose human scale, emotionally you disconnect, and "Ender's Game" crew worked very hard to keep that human scale.

At the end of the interview, Ford was asked to give his thoughts about the Sand Diego convention.

"I don't know man, it's just wonderfully weird. I'm grateful that there's a place for all these people to go," Ford said. "...It's the place where you being the fever for a product like this."

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