Kevin Costner expresses gratitude for support at Horizon: An American Saga premiere

Horizon: An American Saga Chapter 1 hits theatres on June 28, with Chapter 2 following on August 16.

Kevin Costner is thankful for the support he has received for his latest film.

The 69-year-old Academy Award winner attended the premiere of his new epic movie, Horizon: An American Saga, in Los Angeles on Monday, June 24.

At the event, he shared exclusively with PEOPLE how significant this night is to him.

"You think a night like this has the possibility of happening, but for a studio to line up behind it to create this environment for us, to celebrate this movie that we worked so hard for and that we dreamed about for so long, is pretty gratifying," he says, referring to distributor Warner Bros.

The director also tells PEOPLE that his children "are watching over" him at the event, noting "they always do."

Costner has three adult children — Annie, 40, Lily, 37, and Joe, 36 — with his ex-wife Cindy Silva, as well as a son, Liam, 26, with his former partner Bridget Rooney. Additionally, he shares Cayden Wyatt, 17, Hayes Logan, 15, and Grace Avery, 14, with his now ex-wife Christine Baumgartner.

He tells PEOPLE that his children have only seen one version of the film. "I brought them with me to France, but they're anxious to see it with no subtitles," he says with a laugh.

Horizon premiered at the 2024 Cannes Film Festival on May 19. 

Horizon: An American Saga Chapter 1 hits theaters on June 28, with Chapter 2 following on August 16.