Kevin Costner says he's 'really proud' of son Hayes' acting debut in 'Horizon'

Kevin Costner is a proud dad.

Over the weekend, the "Yellowstone" alum shared an Instagram post praising his son Hayes for making his acting debut in the upcoming film "Horizon: An American Saga" nearly a week after the film's trailer dropped.

"When it's your movie you get to pick who you hang out with 👍🏻," he wrote in the caption. "Really proud of my son, Hayes, for making his acting debut in #HorizonAmericanSaga."

Hayes, 15, is one of Costner's seven children.

Costner, 69, also thanked the fans "for all the love" they've shown the trailer, adding, "I couldn't be more excited to share this with you."

"Horizon: An American Saga," directed and co-written by Costner, is a two-part western epic which chronicles "the Civil War expansion and settlement of the American West," according to an official description.

Starring alongside Costner in the films are Sienna Miller, Sam Worthington, Jena Malone and others.

The first part of "Horizon: An American Saga" arrives June 28 and the second installment releases Aug. 16.