At the Venice Film Festival for the movie's maiden voyage, Gosling spoke passionately about the preparation that went behind playing the first man to walk on the moon.
The film, based on James R. Hansen's book, traces Armstrong's journey from family tragedy to the moon landing and what the NASA technicians and astronauts endured along the way.
Writer Josh Singer credited Armstrong's family for helping the filmmakers get "underneath who Neil was", which helped get at "the human as opposed to the icon", deadline.com reported.
Gosling said: "I've never had more help in my life on a film... Whether it was Neil's sons or his late ex-wife Janet or Neil's sister, his childhood friends.. NASA opened the door to the facilities.
"Neil was a very famously introspective quiet humble person so the challenge was to honour that but also to create windows into what he might be or had been experiencing emotionally at the time."
This is Gosling's second film with Chazelle after the musical "LA LA LAND".
Asked what draws him to a director, he quipped: "Good hair is important."
On a serious note, he said: "We met about this film initially and then there was this issue that he had to make a little musical first. Even though they are wildly different both movies were in his head at the same time."
However, Gosling pointed out the similarity in the way the director viewed them.
"They both lend themselves to the big screen. They are both films you would want to experience in an audience with other people.
"Whether it's 'La La Land' or this film, Damien has incredible instincts not only for what the audience wants to see but wanting to unite people through film. This is an incredible story where as complicated as it is and the complicated opinions about it, it unified the world for a certain period of time," he added.