Kevin Costner's Oldest Son Takes Center Stage in 'Horizon: An American Saga' Chapter Two

Kevin Costner reveals that his oldest son, who appeared in a small role in 'Horizon' Chapter One, will also appear in Chapter Two, showcasing the supportive relationship among his seven children.

Kevin Costner's family comes first, and that includes his children's dreams. The Oscar-winning actor told Fox News Digital that his 15-year-old son, Hayes, isn't the only Costner kid to show off his acting chops in "Horizon: An American Saga."

"They're all supportive of each other," Costner confessed of his seven children. "My oldest son was in a scene in chapter two, and, a small part again."

Kevin Costner's Oldest Son Takes Center Stage in 'Horizon: An American Saga' Chapter Two

He joked, "I just try to find ways to trap them."

Costner shares sons Hayes, 15, and Cayden, 17, and daughter Grace, 14, with ex-wife Christine Baumgartner. The former couple finalized their divorce in February after 18 years of marriage.

Kevin Costner's Oldest Son Takes Center Stage in 'Horizon: An American Saga' Chapter Two

He also has three adult children – Annie, Lily and Joe – with ex-wife Cindy Silva, and son Liam, 26, with former partner Bridget Rooney.

While his older son makes his debut in the second part of "Horizon," his son Hayes was only 13 years old when he signed on to star in the first film of the post-Civil War drama which Costner began dreaming up more than 30 years ago.

Kevin Costner's Oldest Son Takes Center Stage in 'Horizon: An American Saga' Chapter Two

"They're all supportive of each other. My oldest son was in a scene in chapter two, and, a small part again. I just try to find ways to trap them." — Kevin Costner

Costner admitted working on set with Hayes, who was cast as Nathaniel Kittredge, was special in many ways.

Kevin Costner's Oldest Son Takes Center Stage in 'Horizon: An American Saga' Chapter Two

"That he did it, that he was good in it, that he listened, that he was worried, that he cared … I'm just so happy that he has that now the rest of his life," Costner said. "I haven't pushed my children into this, and this might be his only dabble in it, but he's memorable. And for me to have him, I'll never forget it."

Hayes' role required two weeks of filming, which gave Costner a unique time to bond with his son.

Kevin Costner's Oldest Son Takes Center Stage in 'Horizon: An American Saga' Chapter Two

"In a sense, it was a smaller part," Costner told "Today" about his son's role. "I selfishly wanted him with me for the week, two weeks, he was with me. And we would drive to the set every day and he would whisper. He didn't have a lot of experience, but he's really beautiful in the movie. It's a really complicated scene.

Costner released the first trailer for the four-part, post-Civil War drama in February, and showcased the Wild West frontier his name has become synonymous with for decades, dating back to his first directorial stint on "Dances with Wolves."

Kevin Costner's Oldest Son Takes Center Stage in 'Horizon: An American Saga' Chapter Two

Costner brought five of his children to the Cannes film festival in May for the "Horizon" debut, including Cayden, Lily, Hayes, Grace, and Annie Costner.

In addition to starring in the feature film, Costner also directed "Horizon," based on a script he co-wrote with John Baird. The ensemble cast includes Sienna Miller, Sam Worthington, Luke Wilson, Abbey Lee, Jena Malone and Giovanni Ribisi, to name a few.

Kevin Costner's Oldest Son Takes Center Stage in 'Horizon: An American Saga' Chapter Two

"I haven't pushed my children into this, and this might be his only dabble in it, but he's memorable. And for me to have him, I'll never forget it." — Kevin Costner

The film came with a hefty price tag, though, and set Costner back many millions in out-of-pocket expenses, which came to light during his divorce proceedings.

Kevin Costner's Oldest Son Takes Center Stage in 'Horizon: An American Saga' Chapter Two

Costner later clarified the massive sum. "I know they say I've got $20 million of my own money in this movie," he told GQ magazine. "It's not true. I've got now about $38 million in the film. That’s the truth. That’s the real number."

Costner invested $38 million of his own money into "Horizon: An American Saga."

Costner's entire focus can remain on the future of "Horizon" now that "Yellowstone" is officially over for Mr. John Dutton. After months of speculation, Costner confirmed on social media last week that he wouldn't be returning to season five, part B of the Taylor Sheridan show.

When asked why he finally made the decision to leave the popular series, Costner's answer was simple. "Because there's just too many questions about it. So the time to step away was now," he told Fox News Digital.

"It was something that really changed me. I loved it and I know you loved it. And I just wanted to let you know that I won't be returning. I love the relationship that we've been able to develop, and I'll see you at the movies."