Actor Josh Brolin was weary of starring as a firefighter in real-life drama Only the Brave because he feared he wouldn't be able to do the job justice onscreen.

The Milk star was already familiar with the risks first responders take, having endured a stint as a volunteer firefighter in Arizona in his 20s, but it was because of his close ties to the community that he was hesitant to sign on for the movie.

"You have a sensitivity that you wouldn't have necessarily had before, and I've spent the last 30 years with this community; one of my best friends is an incident commander now, who was my chief back then (when he was volunteering)...," he explained on U.S. breakfast show Today.

"So when I was deciding to do this movie, you meet a director and you're like, 'Are you gonna be sensitive? Are you connected enough to your heart to be able to do something like this?' and then I went to this guy (his friend), and said, 'Do you think I'm the right guy? Should I do this?' and he said, 'You're the only guy to do this.' It was almost like the appointed one. The fireman touched me and said, 'You're it,' and suddenly I had no choice."

Only the Brave chronicles the tragedy which struck Arizona in 2013, when 19 elite firefighters were killed battling a wildfire near Yarnell.

Brolin plays Eric Marsh, the superintendent of the Granite Mountain Hotshots, in Oblivion director Joseph Kosinski's new movie, and the cast and crew made a point to get to know the families and friends of the firefighters they were portraying onscreen.

"That's what I like about (what) this movie deals with, (it's) equally about firefighting and you're in these extreme situations, but also the extreme situation of what a son deals with, a wife deals with, the entire family," the 49-year-old said. "And these families we met, 19 of these guys, a lot of family, a lot of extended friends and all this kind of stuff, it's a very, very emotional subject, but with this movie you celebrate the profession of firefighting."

Only the Brave also stars Miles Teller, Taylor Kitsch, Jennifer Connelly, and Jeff Bridges, and hits U.S. theatres from Friday (20Oct17).