Updated

Michelle Trachtenberg’s Russian background came in handy when she took on the role of Marina Oswald, the wife of John F. Kennedy’s killer, in the upcoming TV movie “Killing Kennedy.”

Trachtenberg’s character speaks Russian for much of the film, which is based on Bill O'Reilly novel by the same name.

“Before I’d signed on to it, [the script] was predominantly all in Russian,” Trachtenberg told Fox News, explaining that some English was later added. “My mom actually was my translator and broke down the entire script for me.”

She said her mother helped her learn new vocabulary words in the language, such as those relating to guns and killing.

“Marina was a young girl who just wanted to live out the American dream. She just never knew that she would live it out in infamy,” Trachtenberg said of her character.

More On This...

And she had the unique experience of portraying a real-life figure who is still alive today, which presented its own set of challenges, she said.

“She, actually, of the four main players—JFK, Jackie, Lee, and Marina— she’s the only one who is still alive. She’s in her 70s,” the actress explained. “I’m trying to battle with the challenges that she’s still alive, and she may or may not be watching this, and I wanted to honor her living legacy.”

“Killing Kennedy” premieres Sunday at 8 p.m. ET on the National Geographic Channel.