Though Frank Sinatra’s political views shifted to the right at the end of his life, the superstar was originally liberal enough to raise FBI suspicions.

John Wayne, on the other hand, was a devout conservative who opposed Sinatra’s political views. The two men almost got into a physical brawl when Wayne made remarks about Sinatra’s links to John F. Kennedy and a Communist filmmaker.

At least twice throughout his career, Sinatra collaborated with Alfred Maltz, a director who had been banned for communist tendencies and had served time in prison. When a reporter inquired about Sinatra’s recent cooperation with Maltz, Wayne said, “Why don’t you ask Sinatra’s crony, who’s going to run our country for the next few years, what he thinks of it?” Wayne was alluding to John F. Kennedy, whom Sinatra had publicly backed.

Frank Sinatra offers JFK a light at his inaugural, 1961: #Stern pic.twitter.com/1dgwQmBM9J

— Michael Beschloss (@BeschlossDC) December 16, 2018

Because of the backlash against Maltz, Sinatra dismissed him and terminated the project. Later, Sinatra and Wayne were both at a Hollywood charity show. When Wayne seized the microphone, Sinatra “stalked off the stage.”

“What the hell did you walk away from me for?” Wayne later asked Sinatra.

“Well, you cried,” Sinatra said. “You blasted your mouth out.”

The two guys were in the same room a short time later and exchanged some heated words regarding Wayne’s remarks. The two guys almost came to blows, according to sources, before being separated and calmer heads prevailed.

The enmity between John Wayne and Frank Sinatra became so violent that Wayne assaulted Sinatra’s bodyguard when they were both in Las Vegas, according to Carol Lea Mueller’s book “The Quotable John Wayne: The Grit and Wisdom of an American Icon.” The stars were all staying at the same hotel, with Sinatra in the room below Wayne’s. The actor was shooting a movie at the time, and the singer went out to have a good time. When Wayne returned to his room to unwind, he could hear Sinatra’s crew yelling, which kept the actor awake at night.

In his hotel room, Sinatra was throwing one of his renowned parties, replete with incessant chatting, dancing, singing, drinking, and smoking.

Wayne had had enough after a while. He went into Sinatra’s room and asked them to calm down, which they did – for a while.

Wayne phoned again and again until the loudness became unbearable, but no one answered.

That’s when he became enraged.

John Wayne walked down to Frank Sinatra’s room and told the group to stop partying or face the consequences. Despite Sinatra’s calm demeanor in the face of the crisis, his bodyguard was not amused by Wayne’s demanding statements. “Nobody talks to Mr. Sinatra that way,” he got up and informed Wayne.

Wayne’s subsequent actions demonstrated that he had the courage to defend himself.

“Wayne looked at the man, turned as though to go [leave], then turned back swiftly and backhanded the bodyguard, who dropped to the floor,” Carol wrote.

Sinatra’s remark was never recorded, but he knew exactly where he stood with the exhausted Duke that night.

Despite their hostile relationship, something changed in the years after that.

In fact, the two collaborated on a photograph — or, to be more precise, one photograph. Both men starred in the 1966 film “Cast a Giant Shadow,” which was based on the true story of a US Army colonel who joined the Israelis in a war.