After winning the Best Actor Oscar for 1969’s True Grit, John Wayne returned for a sequel with 1975’s Rooster Cogburn – which celebrates its 49th anniversary this week – alongside Katharine Hepburn. However, Duke had severe health issues going back to when he had a cancerous lung removed a decade prior.

Earlier in 1974, Wayne headed to London to shoot the cop movie Brannigan but had a severe bout of pneumonia and was diagnosed with heart problems before production began.

During filming, Duke met Katharine Hepburn, who, despite being just two weeks older than him, had never met the Western star, let alone starred in a movie with him.

She had been filming 1975’s Love Among the Ruins with Sir Laurence Olivier and, despite their political differences, greatly admired Wayne.

The two stars agreed to make True Grit sequel Rooster Cogburn together later that year, although like Brannigan it would not be an easy production.

Alongside pneumonia, Wayne had coughed so hard at one point that he damaged a valve in his heart, an issue that wouldn’t be diagnosed until 1978, a year before he died of cancer. Rooster Cogburn's filming took place in Oregon, and Duke had to rely on his oxygen mask for high altitudes, something he tried to keep hidden from the public. In fact, on another movie, he screamed at a photographer and demanded the film that captured the truth of his ailments; desperate to maintain his macho image.

If this wasn’t bad enough, the 67-year-old injured himself on the Rooster Cogburn set while teaching his eight-year-old daughter to play golf. But lucky for him, his character’s eye patch covered the mark.

Dealing with all these physical problems took a toll on Wayne’s patience and he would become seriously frustrated with Rooster Cogburn director Stuart Miller’s instance on doing multiple takes. In one outburst, Duke ranted: “God damn it Stuart, there's only so many times we can say these awful lines before they stop making any sense at all.”

His co-star Hepburn, who largely respected the actor most of the time, would become bemused by his argumentive nature on set and told him at the wrap party: “I’m glad I didn't know you when you had two lungs, you must have been a real b*****d. Losing a hip has mellowed me, but you!”