Wikimedia Commons/Yellowstone TV show TV Luke Grimes reveals the truth about his relationship with Kevin Costner after the star's shocking exit from the hit series Yellowstone. March 9, 2026 AceShowbiz - The departure of Yellowstone star Kevin Costner shocked fans and cast alike when he left the popular Paramount Network series. Since then, Luke Grimes, who starred alongside Costner, has been candid about their lack of communication following the split. Premiering in 2018, Yellowstone chronicled the trials of the fictional Dutton family, owners of Montana's largest ranch.