Costner has always had the rule when it came to his projects because he is aware that favoritism is common in Hollywood and doesn’t want to unfairly take opportunities from young actors trying to break into the industry.

“I realize there’s so many young actors that would just kill to be in this movie and I don’t want to take those parts away from them just ‘cause I can place my own children in,” he said.  However, the personal reason for casting his son in his upcoming four-part series was actually quite simple: he wanted to spend time with him.

Kevin Costner and his son, Hayes, pose during a photocall for the film ‘Horizon: An American Saga’ at the 77th Cannes Film Festival

“It was a smaller part. I selfishly wanted him with me for the week, two weeks he was with me,” Costner admitted.

In “Horizon,” Hayes Costner makes his debut as Nathaniel Kittredge, the son of Sienna Miller’s character, Frances, per US Weekly. Notably, Kevin Costner’s character, Hayes Ellison, is named in honor of his real-life son.

Costner described his son’s debut performance as “really beautiful.” “It’s a really complicated scene. In the end, there’s a nobility, there’s an absolute fatalness about it. It’s what you want in a son,” he said.

According to CNN, Horizon: An American Saga, the first chapter in a planned series of four films, sets the stage for a narrative exploring the clash between settlers and indigenous people in the American West. The film will debut in theaters on June 28, with subsequent installments following in August.