Kevin Costner had one obvious reason to make Horizon

Aside from being a project three decades in the making, Kevin Costner had one other thing — or person — driving him to make Horizon: An American Saga.

Kevin Costner‘s Horizon: An American Saga is an all-star collection of talent. From Costner himself to other A-listers and members of the Yellowstone cast, there’s no shortage of names in the upcoming Western.

But one addition makes Horizon particularly special, and that’s the inclusion of Costner’s son, Hayes. It turns out, Hayes wasn’t just a member of the cast, but also the inspiration behind getting Horizon completed in the first place.

“I named him after the character I play in this. My character’s name is Hayes Ellison,” Costner said [via ET]. “And I named Hayes that character. So I was watching him grow up and I was thinking, ‘Man, I better get with it and make this movie.'”

Horizon is a passion project 30 years in the making for Costner. But the actor’s eternally busy schedule and commitment to other projects kept pushing Horizon onto the back-burner. Now, after leaving Yellowstone for Horizon, the four-part historical epic is finally coming to life.

What’s more, Hayes’ role in the movie (albeit small) is an important one, according to Costner.

“I captured him and I brought him on, and he’s very good in this small part that he’s done,” he added. “If you see it, I think he has an impact on the movie.”

The 15-year-old actually appears in the trailer, previewing his “impact” in question. In the brief clip, Costner’s son helps Sienna Miller’s character and a small girl (presumably his mother and sister) into an underground shelter. He appears to sacrifice himself, telling them: “It’s all right — I’m gonna be with Dad.”

Horizon: An American Saga Chapter 1 will arrive in theaters on June 28. Chapter 2 will then follow on August 16.