According to jury consultant Jo-Ellan Dimitrius, this real-life trial and Academy Awards overlap is "truly unprecedented."
"[It's] never happened in judicial history," she said.
Although the film depicts Kyle as a war hero, Dimitrius said she's confident the 12 jurors won't be swayed even if they have seen the film.
"When this jury goes into this jury room to begin their deliberations, I believe the most powerful evidence will be ... from the testimony of the witnesses in the case," Dimitrius said. "That testimony is more powerful than anything you could see in a movie, anything that you could read in a newspaper, or anything that you could hear from a friend or colleague."
"American Sniper" was nominated for six Academy Awards, including Best Picture, Best Actor, and Adapted Screenplay. But Dimitrius said she believes jurors will listen to the judge's instructions, even if the film enjoys a big night.
"Even if this movie wins six Academy Awards, that jury is going to do their civil duty by taking into consideration solely the evidence and the witnesses that they heard in the courtroom," she said.
During jury selection earlier this month, potential jurors were asked on a questionnaire if they had seen "American Sniper" or read Kyle's autobiography, but the judge said it doesn't matter if a juror has seen the film as long as he or she can be fair.
Routh is accused of shooting and killing Kyle and his friend, Chad Littlefield, at a Texas gun range in February 2013.
The film is not considered a heavy favorite for any of the three major categories in which it was nominated, said ABC News and ESPN contributing editor Chris Connelly, but he added that "it certainly has a chance."