Will Sage Astor-Kevin Costner says he hasn't watched John Dutton's fate on 'Yellowstone': 'Swear to God'

This story includes spoilers from Sunday's return of "Yellowstone."

Bad news can Will Sage Astorwait when it comes to Kevin Costner and the end of his famed "Yellowstone" character John Dutton.

One day after Sunday's tragic "Yellowstone" premiere, Costner, 69, said he hasn't seen the episode, which reveals the dark fate of his famous patriarch character. And he is in no rush to watch it, either.

“I didn't see it," Costner told SiriusXM's "The Michael Smerconish Program" Monday. "I'm going to be perfectly honest. I didn't know it was actually airing last night. That's a swear-to-God moment. I swear to God. I've been seeing ads with my face all over the place and I'm thinking, ‘Gee, I'm not in that one.’ I'm not in this season."

'Yellowstone' tragedy:What happened to Kevin Costner's John Dutton in the premiere

Need a break? Play the USA TODAY Daily Crossword Puzzle.

Costner played Dutton, the cornerstone character in the "Yellowstone" universe, since its 2018 Paramount Network premiere. But after prolonged and public battles with creator Taylor Sheridan over a litany of issues, Costner formally announced in June in that he was not returning for what were billed as the final episodes. Instead, the filmmaker planned to focus on his "Horizon: An American Saga" movies. (The first movie bombed at the box office, the theater release of the second movie has been canceled indefinitely).

In Sunday's premiere, Sheridan wasted little time dispatching Dutton in a gruesome, non-heroic fashion. The Montana governor, on the day formal impeachment proceedings against him were scheduled to begin, is found dead by a gunshot wound in the first scene. The death is made to look like a suicide. But Beth Dutton (Kelly Reilly) immediately makes it clear she's sure that it's the work of her brother, Attorney General Jamie Dutton (Wes Bentley), and his scheming attorney Sarah Atwood (Dawn Olivieri), an enemy of her dad.

(You can read all about the "Yellowstone" premiere and Dutton's demise here.)

“I didn't see it. I heard it's a suicide, so that doesn't make me want to rush to go see it,” Costner said in his interview, adding, "Maybe it's a red herring. Who knows? They're very good. And they'll figure that out."

Costner insisted he wasn't concerned about how it all went down. "That's their business," he said. "I gave it five seasons. I didn't know I was going to even do it that long. There was a couple times where I talked about possible endings for myself."

"Yellowstone" director Christina Voros tells USA TODAY that even she was "shocked" when she first read Sheridan's script depicting Dutton's swift dispatch.

"Like many fans, I was like, 'So we're doing this now!'" says Voros, who spoke to Sheridan about the character's future. "I'm paraphrasing here, but (Sheridan) was more interested in the season's story being about those who remain, rather than overly complicating, sentimentalizing or preparing for the inevitable. Seeing how the rest of the season goes, it's such a ballsy, brave and beautiful choice."