Sam Elliott reveals big tearjerking moment with Bradley Cooper in 'A Star Is Born' was unscripted (SPOILERS)

Warning: A Star Is Born spoilers ahead.

Sam Elliott didn’t know what Bradley Cooper was going to say. He knew the broad strokes of the message, but he didn’t know the line.

The exchange leads to one of the most memorable, heart-wrenching images from A Star Is Born, the new Cooper-directed box office hit that also births pop star Lady Gaga‘s movie stardom. Self-destructing rocker Jackson Maine (Cooper) is having it out with his brother and tour manager, Bobby (Elliott), in Bobby’s pickup truck. Their relationship has been through the ringer a few times over now, and it’s always been complicated by their respective memories of their long-dead father, who taught Jackson to sing. But as Jackson stands outside the vehicle, he hits his much-older brother with an emotional whopper: It was him Jackson idolized and emulated, not their dad.

A moment later, Bobby turns to back up his truck, and the rugged music vet who’s seemingly seen everything all these years looks over his shoulder with bloodshot, tear-soaked eyes. (It’s a moment made all the more tragic, considering the film’s subsequent events.)

“This speaks of Bradley [as an] actor-director,” Elliott (The Big Lebowski, The Hero) said in recounting how they filmed the scene to Yahoo Entertainment (watch above). “We pulled into the driveway after having the words on the road, and then the door opened, and Bradley just stood there and he kind of hemmed and hawed and I wasn’t sure what was going to come out of his mouth. I knew the gist of it, but I didn’t really know what he was going to say. And then he said what he said, and shut the door, and was out of the shot. And somebody handed him a little monitor, and all the sudden he was the director.”

What followed (meaning all that welling up) was completely unscripted and unplanned.

“I was still trying to be in the moment of what I was doing, but I was watching [Cooper] walk around [the truck] and he was looking at this monitor. The monitor was of the camera behind me. And the only reason I turned around was to back out of the shot. It wasn’t to [show my face]. That’s where I was at the moment.”

Elliott teared up again describing it all.

“I figured we were going to do another take. And he just said, ‘No, man. We got it.’ That was the first take. It’s one of those wonderful moments that you get to have or you don’t. There were a lot of those moments in this piece, and it’s because of Bradley’s ability to create that environment, and give you the chance to get at that truth. He’s a wonderful director.”

It’s a moment that could very well propel the 74-year-old screen vet Elliott to his first Oscar nomination. And we can safely guess what clip they’ll use for his reel.

A Star Is Born is now in theaters.

Watch Bradley Cooper talk about Eddie Vedder’s surprising influence on his performance:

Read more on Yahoo Entertainment: