At Chris Kyle's funeral, Country musician Randy Travis appeared to perform "Amazing Grace". Earlier drafts of the screenplay included his rendition over the funeral, but in the final movie, it was replaced with "The Funeral" by Ennio Morricone.
Along with all of the other Star Wars connections, Ian McDiarmid, who played Arthur the butler in this movie, played Emperor Palpatine/Darth Sidious in the Star Wars film franchise.
After Ryan Gosling and Nicolas Winding Refn removed much of the Driver's dialogue, Bryan Cranston felt that his character, Shannon, should make up for the lack of talking in the film, and thus made Shannon a motormouth. Much of his dialogue is improvised.
Based upon director Helmut Dietl's experience of trying to adapt Patrick Süskind's novel "Das Parfüm" into a movie. Uhu Zigeuner is based upon Dietl, while Jakob Windisch is based upon the author Süskind. Oscar Reiter is based upon producer 'Bernd Eichinger' who eventually would turn the novel into a film, Perfume: The Story of a Murderer (2006).
Mel Gibson was investigated by an animal welfare organization, which was convinced that the fake horses used were real. Only when one of Gibson's assistants provided some videotaped footage of the location shooting were they convinced otherwise.
Because of the Columbine massacre, the producers were pressured into toning down the film's violence. (At one point, the studio attempted to demand for no blood to be seen in the film at all). As such, the film is a bit more satirical and comedic than the first two.
As the elderly Rose exits the helicopter in her wheelchair, she is holding her pet Pomeranian. This is in tribute to the 12 confirmed dogs on the Titanic. Only three pets survived: two Pomeranians and one Pekinese which, due to their small size, were smuggled onto lifeboats.
Industrial Light & Magic spent most of the production period in chaos, attempting to create special effects that had never been created before. They blew half their budget on four shots which George Lucas rejected. Ultimately, around $5 million of the $8 million budget was spent by Industrial Light & Magic.
When Kamante wakes Karen to warn her about the fire, the actual real-life event was not about the fire at the coffee factory, but a long, thin, winding rivulet of fire that Kamante had seen in the blackness of night as the Maasai performed their burning of the grass on the Athi plain, which was done to promote new growth grass for their cattle. They would do this not long before the long and short rains would come in October and March.
Chris Gardner helps Jay Twistle solve his Rubik's Cube. In the The Fresh Prince of Bel-Air (1990)'s episode "Alma Matter" (season 3, episode 18), Will Smith gets into Princeton University after solving Ed's Rubik's Cube.
Bradley Cooper said that Lady Gaga was the one who convinced him they should sing live. Gaga said she hated watching movies where the actors were not lip-syncing correctly to the songs, and to avoid this and get it right they needed to sing live for the film. This was what caused Cooper to get more extensive vocal training.
David Leitch has stated that the film would feel different from the "Fast and Furious" franchise. Although it was filled with action sequences, cars and elements that constructed "Fast and Furious", it would feel different from the series.
Alternate Ending: Tornatore filmed a different ending to this film, the location was a restaurant in Rome. The same location is used for a momentary earlier scene, but the end-scene filmed on the same Rome set was cut and replaced with a more elaborate scene and slightly modified dialogue filmed in a different international location.
The film's subject matter was conceived of when Christopher Nolan was joined by his brother Jonathan on a late summer cross-country road trip, as Christopher was moving to Los Angeles and Jonathan had time before returning to his studies at Georgetown to spend time with his brother and help with with the move. By the time they arrived in L.A., the entire screenplay had been stated out loud between the brothers.