John Travolta unpacks 'most challenging' role yet in 'November 1963' | Exclusive

John Travolta has played a blue-collar reveler (“Saturday Night Fever”), a body-swapping FBI agent (“Face/Off”) and a big-hearted Baltimore housewife (“Hairspray”).

And yet, nothing could have prepared him for “November 1963” (in theaters Dec. 4), a gritty new drama that depicts the mob’s alleged role in President John F. Kennedy’s assassination. Travolta, 72, portrays Johnny Roselli, a high-profile mafioso in the Chicago Outfit who was recruited by the CIA in an unsuccessful plot to assassinate Cuban dictator Fidel Castro. A few years later, he allegedly helped to orchestrate Kennedy’s killing as well.

“This would be up there with the most challenging [roles] for sure, because I had to start from scratch,” Travolta tells USA TODAY, which has an exclusive first look at the movie's new poster and images. “There’s no actual footage of him – only what you read in books and photographers and stories that [screenwriter Nicholas Celozzi] would tell me, so I had a lot of questions.”

Celozzi was inspired to write “November 1963” after conversations with his uncle, Joseph “Pepe” Giancana, whose brother, Sam, was a prominent Chicago mobster. The film alleges that the mob felt betrayed by the president’s handling of Cuba and crackdown on organized crime, after purportedly helping to secure Kennedy votes and land him in the White House.

The movie suggests Jack Ruby (Robert Carlyle) was enlisted to take out gunman Lee Harvey Oswald (Jefferson White) so he wouldn’t expose the mafia’s role in Kennedy’s assassination, although there is no official evidence supporting this.

“I knew about the [mob] involvement in my family since the day I was born,” Celozzi recalls. His goal in writing this movie was to show that these men were not merely gangsters but “real people."

"This was back in an era where there was a lot of complexity with these individuals," he says. "They were actually heroes of the neighborhood. If you didn’t bother them, you wouldn’t even know what they did. They were revered and very generous.”

Roselli was a debonair Hollywood playboy who allegedly ran in the same circles as Frank Sinatra and Marilyn Monroe. But he also lived a double life as a fearsome fixer in Los Angeles and Las Vegas. In 1976, at age 71, Roselli was found dead in a barrel floating off the coast of Miami with his legs sawed off. His murder was never solved.

“He was a professional hitman and a sharpshooter at that,” Travolta says. “There was a lot of: How do we connect these dots? How are we making him human yet behaving in a detached way? There’s a paranoia about all these guys. They were always looking over their shoulder, never really knowing whether this was their last day.”

Travolta worked extensively with Celozzi and director Roland Joffé to figure out Roselli’s wardrobe, body language and cadence.

“I didn't use an accent because he came from Italy to New York to Chicago,” Travolta says. “I made him somewhere not as identifiable, which was correct. Also, he comes from Hollywood; he's putting people in movies and collecting under the table for every studio. He’s quite connected, so I gave him a real showbiz attitude.”

Celozzi had met the real Roselli as a little kid and felt the resemblance was uncanny.

“Some of those moments, I would just look at John, and I got chills,” Celozzi says. “When something's working, it's working. I would just close my eyes, listen, and I’d be back in Chicago. It was chilling sometimes.”