Kevin Costner didn’t tune in for his character’s final appearance on "Yellowstone" Sunday night.
On SiriusXM's "The Michael Smerconish Program," Costner admitted, "Well, I'm going to be perfectly honest. I didn't know it was actually airing last night."
He continued, "That's a swear to God moment. I swear to God. I mean, 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. But I've been seeing, but I didn't realize yesterday was the thing. I really have, my focus has been on what I was having to do, and I've got a few calls to make.
"Sometimes I'm like just a passenger in my life, you know, there's a lot going on," Costner added. "And somebody said, you know, it played last night? And I said, ‘Hmm, okay.’ So no, I found out about it this morning, actually."
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Sunday night’s episode featured Costner’s character, John Dutton, appearing to have been shot and killed after being discovered by Kelly Reilly and Luke Grimes' characters, Beth and Kayce Dutton.
The death appeared to be a suicide, but there seems to be some suspicion that he was actually murdered.
"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 of the episode.
When Smerconish said Costner’s character didn’t seem like a character to die by suicide, the actor replied, "Well, they're pretty smart people. Maybe it's a red herring. Who knows? They're very good. And they'll figure that out."
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The "Dances with Wolves" star also said he hadn’t been aware of how his character would exit the show.
"No, no, that’s their business. I gave it five seasons. I didn’t even know I was going to do it that long. There was a couple times where I talked about possible endings for myself," he said.
He added, "Listen, they’re smart people. Whatever they’re doing, they’ll figure it out. But I had come up with two possible endings back when I wasn’t going to [do it as] long as it did go."
His co-star, Grimes, who plays Costner’s son on the show, previously told Fox News Digital "none of us saw it coming."
"I didn't see it. I heard it's a suicide, so that doesn't make me want to rush to go see it."
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"None of us ever knew when that was going to happen or how. And so, you know, it happened in a way that kind of I guess none of us, you know, saw it coming. But we were all kind of preparing for that at some point. And, you know, whose character does what. And it was really fun to sort of be on that journey with the audience," he said.
Grimes did say he had been "a little disappointed" that the "Yellowstone" cast were not aware that Costner wouldn't be returning to conclude the fifth season.
WATCH: 'YELLOWSTONE' STAR LUKE GRIMES ADMITS 'NONE OF US SAW' KEVIN COSTNER'S EXIT COMING
"I guess I was probably a little disappointed that we didn't know that he wasn't going to be, you know, back," he began. "I think there might have been a better goodbye had we done it in some other way. It was, you know, it was more of a surprise than anything."
"But like I said, that's above my pay grade. And our job is just show up and do what's on the page and do it to the best of our ability," Grimes said.
On "The Michael Smerconish Program," Costner said "I didn’t quit the show."
He explained that the issue came down to schedules and contracts, in part with his "Horizon: An American Saga" film series.
"Well, they're pretty smart people. Maybe it's a red herring. Who knows? They're very good. And they'll figure that out."
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"Yeah, I didn't really have to leave anything behind. There were the gaps that were there. There was contractual things that would allow for both things to be done, but because both things were contractual, you had to make room for the other thing. There was room, but it was difficult for them to keep their schedule," he explained.
"It seemed to be, it was just too difficult for them to do it. There was the time there, what happened, you can deal with it. But no one, I didn't leave. I didn't quit the show. OK?
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"I had made a contract to do all three," he continued. "There was a contract in place to do all three. And within about an eight-month period, two more different kind of contracts were being negotiated. Not at my request, but at their request to try to do things.
"I accommodated them on those extra two things that changed. Things change, and finally when they wanted to change it a third time, because I had my obligations to do, I had 300 people waiting for me, I couldn't help them anymore. I just simply couldn't help them. But I didn't quit the show. There was no, there was just a, you know, everybody has to live up to what they say they're going to do. And it doesn't matter what business you're in."
Costner has said he’s still open to returning to the show "Yellowstone" if it works out.
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In September, he told Entertainment Tonight, "That's been a wonderful part of my life, you know, making 'Yellowstone.' And who knows, sometimes some things have a way of circling back. I haven't seen that dust trail coming toward me. But I've always been open to what I started. And the five seasons was a lot for us to do. I think that, you know, that story is not finished."
Fox News Digital's Janelle Ash, Larry Fink, and Emily Trainham contributed to this report.