King Charles' health and cancer recovery questioned again following 'Gladiator II' premiere

King Charles III waited a long, long time to ascend the throne in the United Kingdom -- but few are certain as to whether his reign will extend much beyond 2024.

Charles has been battling cancer throughout the year, only his second full year on the throne following the death of his mother, the long-lived Elizabeth II. At 76 years old, Charles' advancing age is doing him few favors as he tries to beat back the disease; aides have been caking him in makeup for recent photos and public appearances, while the stress of his royal duties -- not to mention infighting between his sons Harry and William -- do not exactly accommodate someone in poor health.

Paul Mescal and Denzel Washington offer a window into Charles' current state

Among Charles' royal duties was to attend the UK premiere of the highly-anticipated film "Gladiator II", the sequel to director Ridley Scott's 2000 Roman Empire epic "Gladiator". Scott is back on board as the sequel's director, and he recruited star power in Paul Mescal and Denzel Washington for lead roles in the new film.

But Mescal was not exactly thrilled to meet Charles -- in part owing to his proud Irish ancestry, and because he had trouble understanding the King.

"I found it somewhat challenging to fully catch what (Charles) was saying, so I ended up just nodding along and smiling," Mescal revealed to the trade magazine Variety.

Mescal's co-star Washington offered even less respect to the monarch of a kingdom whose leaders' colonial ambitions altered the globe's political alignment and social structures. Washington -- one of the most decorated American actors of his generation -- told security on the night of the "Gladiator II" premiere that he "makes his own rules" and would not go inside the venue to meet Charles upon his arrival.

Increasingly, as Charles' condition is called into question, reactions to his appearance -- beyond that which is physical -- will be closely monitored, as will his reaction with others. Only time will tell if Charles steps back from the royal duties he always coveted in order to focus fully on the most important battle of his life.