Brad Pitt and Leonardo DiCaprio among the many A-Listers who turned down Brokeback Mountain

It went on to become one of the greatest Oscar snubs of all time (as well as taking home three Academy Awards), but gay cowboy drama Brokeback Mountain proved one of the most challenging films to cast, if a recent Gus Van Sant interview is anything to go by.

Leonardo DiCaprio, Bradd Pitt, Matt Damon and Ryan Phillippe were among the Hollywood heavyweights who turned down the leading roles, of Ennis Del Mar and Jack Twist, for the 2006 film.

“Nobody wanted to do it,” Van Sant told IndieWire. “I was working on it, and I felt like we needed a really strong cast, like a famous cast. That wasn’t working out. I asked the usual suspects: Leonardo DiCaprio, Brad Pitt, Matt Damon, Ryan Phillippe. They all said no.”

Van Sant worked on the film before Ang Lee stepped in – and became the first Asian winner of the Best Director Oscar in the process. Van Sant has since gone on to direct Milk, a biopic of the gay rights activist Harvey Milk, and recent release Don't Worry, He Won't Get Far on Foot. 

Instead, Jake Gyllenhaal and the late Heath Ledger were cast, with Ledger taking the role of the more repressed and introverted Ennis. "Casting Ennis in particular was the ultimate hurdle," said the film's producer Diana Ossana, who confirmed that the above names "turned down the project, for various reasons".

The film earned both Best Actor Oscar nominations, and made an enormous difference in challenging the long-held notion that straight men would ruin their acting careers by taking gay roles. Ledger went on to earn a posthumous Oscar for his performance as The Joker in 2009.

DiCaprio, meanwhile, didn't pick up an Oscar until 2016, for The Revenant, although he had been nominated for Best Actor three times previously. 

DiCaprio and Pitt will closely share a screen next year, in Quentin Tarantino's Once Upon a Time in Hollywood.