John Wayne’s Rio Bravo remake El Dorado had him co-starring opposite Robert Mitchum, with whom Duke became firm friends on the 1966 movie.

When the director of both films Howard Hawks wanted to make the film about a sheriff defending his office from outlaws for the third time, he hoped he could convince his starring pair to return.

And when the filmmaker first approached Duke about 1970’s Rio Lobo, the Hollywood star replied: “Do I get to play the drunk this time?”

Hawks also wanted Mitchum to reprise his drunken sheriff, but the actor said he was retired. Despite this, his son Christopher Mitchum bagged a role in the movie, his second with Wayne that year after Chisum.

The young actor would go on to co-star with the A-lister in 1971’s Big Jake, playing one of Duke’s sons alongside the Western legend’s actual kid Patrick Wayne.

Sadly, this was the last movie that Christopher would act in opposite Wayne after a terrible feud that saw them never speak again.

This was sparked soon after Big Jake release when the co-stars appeared together on The Tonight Show with Johnny Carson on June 7, 1972.

Wayne was well known as a staunch and uncompromising conservative and during the TV interview, they disagreed on a political issue of the day. Their conversion ended by talking about environmentalism, which the Western legend wasn’t in favour of. It was his belief that if you were an environmentalist, then you were against business. And if you were against business, then you were a liberal.

Over the years, Christopher desperately tried to get back in contact with Wayne to reconcile. However, Duke didn’t let go and never responded to the attempts, even when he was dying from cancer in 1979. The 72-year-old Western legend made his final public appearance at the Oscars that year, noticeably very thin. Arriving to a standing ovation, he secretly wore a wet suit under his tuxedo to help bulk himself up a bit.

Wayne was there to present the Best Picture Oscar to The Deer Hunter and thanked the audience for their supportive applause.

He said: “Thank you, ladies and gentlemen. That’s just about the only medicine a fella would really ever need. Believe me when I tell ya, I’m mighty pleased that I can amble down here tonight.

"Well, Oscar and I have something in common: Oscar first came to the Hollywood scene in 1928, so did I. We’re both a little weather-beaten, but we’re still here and plan to be around for a whole lot longer.” Sadly, the Hollywood legend died just two months later on June 11.