4 interesting facts about the production of ‘The Godfather’ – like how that horse's head was actually real

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The Godfather is one of the most critically lauded films of all time, winning best picture at the 45th Academy Awards, among many other prestigious accolades.

Released on this day in Australia (November 2) in 1972, the gangster drama is based on the novel of the same name by Mario Puzo and was directed by Francis Ford Coppola. The Godfather follows the story of New York crime family, the Corleones, as its youngest son is reluctantly drawn into the dark family business.

While most movie buffs will be familiar with the film and its sequels, there are a number of interesting facts when it comes to the production of the iconic original.

To celebrate the anniversary of The Godfather, here are 4 things you might not know about the making of The Godfather. If you haven't seen the film, there are of course a few spoilers ahead.

1. One of its best lines was improvised

As he leaves his house to take care of a particularly devious job, Peter Clemenza's wife tells him, "Don't forget the cannoli," which was a last-minute addition to the script. After a long drive, Rocco fires three shots while Clemenza relieves himself on the side of the road, signalling the hit had been completed.

When returning to the car, Clamenza says the iconic line, "Leave the gun – take the cannoli," the latter half of which was completely improvised by actor Richard Castellano. Years after the release of the film, Coppola credited the actor, saying that "Richie improvised the line".

2. The horse's head was real

Perhaps one of the most iconic scenes in movie history, it shows the character Jack Woltz waking up with a severed horse's head in his bed. While a fake head was used during rehearsals, Coppola swapped it with a real one for the actual shot, meaning the screams you hear from actor John Marley were absolutely genuine.

According to TIME, the crew located a horse ready for slaughter at a New Jersey dog food plant that looked like the one in the movie. The art director told the plant, “When that one is slaughtered, send us the head.”

3. One famous scene was actually a mistake

Luca Brasi was played by a former pro wrestler named Lenny Montana, and when it came time to deliver his lines to Marlon Brando, he was so nervous about the scene he couldn't get a single good take, even after a full day of shooting.

The production didn't have the time to spend another day on the scene, so Coppola instead added a new scene where Brasi rehearsed his lines before seeing the Godfather so his failed takes made it look as though he was just nervous about the meeting.

4. Many rehearsals were simply family dinners

Instead of holding formal rehearsal sessions, Coppola instead hosted dinners the main cast would attend as their characters. The director later revealed that the dinners were vital for the actors and that they really helped them established their roles in the film.

"After that dinner, it made me realise that improv with food is very lasting, and [the actors] sort of had who they were gonna be after that," Coppola said at the 2017 Tribeca Film Festival.

The Godfather is available to watch on Stan right now, as well as The Godfather Part II and Part III.