Oscars 2019: The true story behind Oscar-winning film Green Book.

For months on end, Green Book has been tipped to be one of the year’s top Oscar award winners.

And during tonight’s Academy Awards ceremony, it turned out the speculation was spot on.

The film, which stars Viggo Mortensen and Mahershala Ali, won three out of its five nominations, including Best Original Screenplay, Best Supporting Actor and Best Picture.

But what many might not know is that Green Book is actually based on a true story.

Watch the official trailer for Green Book here. Post continues below…

What is the true story behind Green Book?

Green Book follows the real life story of Jamaican-American pianist Dr Don Shirley (Mahershala Ali) and Italian-American bouncer Frank Anthony Vallelonga (Viggo Mortensen).

In 1962, when Shirley was preparing to set out on tour, he hired Vallelonga, commonly referred to as Tony Lip, to handle any problems he may encounter as her travelled across America.

At the time, racial segregation was strongly enforced in the Jim Crow-era South and for black musicians, travelling there was incredibly dangerous.

Black musicians who travelled to the South were often met with racial slurs and violence and not long before Shirley hired Lip, fellow performer Nat King Cole was brutally assaulted on stage in Alabama by the Ku Klux Klan.

“My father said it was almost on a daily basis they would get stopped, because a white man was driving a black man,” Lip’s son Nick Vallelonga recalled.

Although Shirley and Lip were an unlikely pair, they soon became close friends as they spent a year together on the road.

When the pair first met, Lip was reportedly a racist.

In the movie, Lip often used racist slurs and made stereotypical assumptions about Shirley.

But after seeing the treatment of Shirley, including how he was banned from eating in the restaurants where he performed or use their bathrooms, Lip's mindset soon changed.

"All that [racism] went away after he became friends with Dr Shirley, and after this crazy trip they took together and what happened to them," Lip's son Nick Vallelonga, who wrote the movie, said.

Returning from the tour, Lip's mindset was completely changed.

According to Lip's son, he even began instilling the belief in his children that everyone is equal.

Both Lip and Shirley passed away in 2013.

It's believed the pair remained friends up until their death.

What does the title Green Book refer to?

The film's title comes from The Negro Motorist Green Book, which is most commonly known as The Green Book.

The book, which came about in the segregation-era in America, was a guidebook for African Americans about which restaurants, rest stops and hotels would serve black people.

Created by African-American postman Victor Green, the guidebook was first published in 1936 and sold for 25c.

Although the first edition of the book only focused on the New York area, the guide soon expanded to include all 50 states as well as Mexico and Canada.

In 1956, Green left his job as a postman to dedicate himself to the guide full time as he opened a travel agency.

Following its initial release in 1936, the book continued to be published annually for the next three decades.

Throughout the movie, Lip and Shirley refer to the book as they travelled through America's South.