A surprising word keeps popping up on the press tour for Peter Farrelly’s Green Book. The word is “truth.”

The movie hasn’t exactly been a runaway hit—its box-office take-home has been slow but steady, with encouraging signs of growth over the past couple of weekends. Maybe awards momentum has something to do with that. Last week, the Hollywood Foreign Press Association honored Green Book with five Golden Globe nominations, in acting (for both Viggo Mortensen and Mahershala Ali), writing, direction, and for best musical/comedy. The National Board of Review had already dubbed it best picture of the year, and the American Film Institute ranked it among their top 10 for the year. Audiences at the Toronto Film Festival, meanwhile, had already given it the People’s Choice Award over a crowded lineup of movies that included Bradley Cooper’s A Star Is Born.

Some of that is undoubtedly thanks to the movie’s subject matter—and its veneer of truthfulness. “There’s a lot of stories about racism that have been told, are being told, and should still be told,” said Nick Vallelonga, one of the film’s screenwriters, in one interview. “It happened to my father the way it happened.” Vallelonga is son of the film’s protagonist, Tony “Lip” Vallelonga—an Italian-American bouncer played by Mortensen who gets hired to escort a black pianist, Dr. Don Shirley (Ali), on a tour of the Jim Crow South in 1962. They travel in a delectably suave teal Cadillac befitting Shirley’s kingly stature and brisk demeanor.

The idea is that though Shirley is an esteemed cultural figure, this status won’t mean much to the era’s “sundown towns”—all-white municipalities with strict legal and social codes dictating who belongs. Tony Lip is there for protection. “I don’t want to manipulate that,” Nick Vallelonga said of his approach to the script. “I don’t want to do anything but the truth.”

“Every single event in this movie actually happened,” writer and producer Brian Currie told The Hollywood Reporter—including an astonishing incident in which Shirley leans on Robert F. Kennedy to get him and Lip sprung from prison. “Everything was real. I’ve known Tony Lip for 25 years. I’ve heard the stories. They’re all true. This is a true story.”

So Green Book isn’t merely inspired by history, we’re told, or based on a true story: it is the “true story,” written by family, and furthermore, it depicts a “true friendship.” Certainly there are nuggets of historical reality to acknowledge here: Tony Lip really was an Italian-American bouncer from Paramus, New Jersey, who worked the Copacabana before being hired to escort Dr. Shirley on a tour of the South. Dr. Shirley, meanwhile, really was a concert and jazz pianist—an outright prodigy, who, as the movie depicts, lived with regal splendor in an apartment above Carnegie Hall. That 1962 road trip undergone by the two men? That really happened too, though it lasts about two months in the film while, in real life, it lasted about a year. Importantly, the two mens’ friendship is said to have lasted until they died four months apart in 2013.

You’d think that would give Farrelly and his team a lot to work with. This is a decades-long friendship we’re talking about, with a script written by the son of the lead character—who, though he was only 5 years old in 1962, has said he remembers visiting Shirley atop Carnegie Hall as a kid. There should be ample opportunity for intimate familial realities to sneak their way into the movie. Vallelonga still has tapes of his father recounting incidents he ended up including in the script.