The new movie – which has had exceptional early reviews – is about the moon landing, with Ryan Gosling playing the late Neil Armstrong.
However, the historic moment that Armstrong planted the American flag on the surface of the moon does not feature – prompting something of a mild furore.
Now, Buzz Aldrin – himself an iconic astronaut – has taken to Twitter to strongly hint about the side of the debate he falls on.
He posted photos of the flag on the surface of the moon back in 1969, alongside the hashtags #proudtobeanAmerican, #freedom, #honor and #onenation.
The snaps have had 11,000 Retweets and 27,000 Likes since he shared them in the early hours of this morning.
Gosling himself had previously defended director Damien Chazelle’s choice to omit the flag.
“I think this was widely regarded in the end as a human achievement [and] that’s how we chose to view it,” he said, according to CNN.
“I also think Neil was extremely humble, as were many of these astronauts, and time and time again he deferred the focus from himself to the 400,000 people who made the mission possible.”
Armstrong’s sons, meanwhile, have sided with the film-makers.
“This is a film that focuses on what you don’t know about Neil Armstrong,” they said via a statement to Collider.
“It’s a film that focuses on things you didn’t see or may not remember about Neil’s journey to the moon. The filmmakers spent years doing extensive research to get at the man behind the myth, to get at the story behind the story.
“It’s a movie that gives you unique insight into the Armstrong family and fallen American Heroes like Elliot See and Ed White. It’s a very personal movie about our dad’s journey, seen through his eyes.
“This story is human and it is universal. Of course, it celebrates an America achievement.
“It also celebrates an achievement ‘for all mankind, as it says on the plaque Neil and Buzz left on the moon. It is a story about an ordinary man who makes profound sacrifices and suffers through intense loss in order to achieve the impossible.”
They went on to clarify that they “do not feel this movie is anti-American”.
First Man is out on October 12.