Alejandro González Iñárritu defended the blown up budget of his upcoming film, "The Revenant," starring Leonardo DiCaprio.

The revenge drama's original production cost was previously at $95 million, but The Wrap reported from multiple sources with knowledge of the production claimed that the film's budget has now climbed to an estimated $135 million.

"It was very difficult production," said one of The Wrap's sources. "We were really biting off a lot more than we could chew. The movie just kept getting bigger and bigger, more complicated, the weather - waiting for the light to be a certain way."

Just recently, Iñárritu gave three reasons why a project exceeds its primary production cost: including "when you don't know what you want and you don't know how to get it, when you know what you want but you don't know how to get it," and refusing to compromise, according to The Hollywood Reporter.

The Mexican filmmaker continued, "We all knew what we wanted, we knew how to get it, but every obstacle was in the way [of what] we needed, and we knew what we needed. ... No scene was added, everything was written, but we were just trying to accomplish what we had from the beginning."

The Hollywood Reporter added that the movie's original budget "wasn't based on any reality, no one had done any location scout or production schedule, it was just lawyers making a deal," New Regency president and CEO Brad Weston said that "The Revenant" became "a living, breathing movie" along the way, adding that Iñárritu's every single creative decisions "made the film better," the news outlet further reported.

Weston continued, "Great directors make great movies. Executives don't."

The movie is based on the true story of Hugh Glass, a 19th century frontiersman who was mauled by a bear and vows to exact revenge on his team for betrayal, robbing him, and leaving him for death, Variety reported. Glass battled difficult winter conditions in his 200-mile journey to redemption.

Also starring in the upcoming film are Tom Hardy, Domhnall Gleeson, and Will Poulter, the news outlet added. Inarritu and Mark L. Smith penned the movie's screenplay, which is based on Michael Punke's 2002 novel with the same name, The Verge wrote.

The movie is being shot sequentially to highlight the changing seasons, with filming done using only natural light by award-winning cinematographer Emmanuel Lubezki, The Wrap reported. But production halted for six weeks because of the lack of snow in Canada, one of the production's locations. The team had to move production to Argentina from Calgary to find snow.