Kevin Costner is promoting his new film, 'Horizon: An American Saga - Chapter 1,' which chronicles the American west's expansion during a 15-year span around the Civil War. The film, featuring a star-studded cast and his son Hayes in a minor role, will be released in two parts. Despite his departure from 'Yellowstone,' Costner expressed willingness to reprise his role as John Dutton under the right circumstances. He cited scheduling conflicts with 'Horizon' and a desire for more frequent work as reasons for his initial exit. Costner emphasized his love for 'Yellowstone' and remains open to returning if the story aligns with his interests.