The pitch for a Kayce spinoff “really roped me in,” the newest High West brand ambassador tells PEOPLE. “And I think it will rope the audience in as well.”

Luke Grimes in ‘Yellowstone’. Credit :

Luke Grimes wasn’t going to return to the Yellowstone world just for the sake of it.

The 41-year-old actor wanted there to be a reason for him to reprise his beloved character Kayce Dutton after the hit Taylor Sheridan series came to an end last fall, and he wasn’t going to say yes to a project just because saying goodbye to Yellowstone was “really hard,” he tells PEOPLE.

In May, CBS announced that Grimes’ character would be getting a spinoff series, titled Y: Marshals, but he says that it wasn’t until the right story came his way — one that he knew would “rope the audience in” — that he was on board.

Grimes was sure it was the “end of the road” for Kayce when Yellowstone ended and was not under the impression he’d get a spinoff.

“On the last day of shooting, I thought it was my last day as Kayce. It was over to me,” he says of the conclusion to season 5, which aired in December.

“It was seven years of playing a person that I’ll never see again, except for having his hat and jacket in my closet. It wasn’t until probably three or four months after that that everything started aligning for the [spinoff].”

Wrapping filming on Yellowstone was “a lot bigger of a life moment than I thought it would be,” he admits. “To try to put that show away, it was hard. It was really hard, and I know this is going to sound weird, but it was sort of emotional. It was like losing a family in a way.”

Still, Grimes thought it was “the end of the road, which would’ve been fine were it the case,” especially considering Kayce “sort of gets what he has been looking for, his dream life” at the end of Yellowstone.

Y: Marshals will “find a whole new world” for the youngest of the Dutton clan, in a way that “makes sense.”

When the idea of a spinoff was raised, Grimes’ first thought was, “Where do you go from there?”

In the finale, Kayce is “back to who he really is and his soul” after selling the Dutton land to Chief Thomas Rainwater (Gil Birmingham), but when there “finally came along a really good idea” for a continuation, he was in.

Cole Hauser, Luke Grimes, Kevin Costner in ‘Yellowstone’ season 3.Cam McLeod/Paramount Network/Courtesy Everett Collection

“We definitely wanted to make sure to give it a real story and make it interesting and make it believable,” Grimes, who has partnered with High West as the whiskey’s newest brand ambassador for its Protect the West initiative, says.

“If it was just like, ‘well, he’s happy’ — we’re just going to watch him be happy? That’s not very cool. But I’ll say this, the idea that was pitched to me is very, very good and very interesting and it really roped me in and I think it will rope the audience in as well.”

Returning to Kayce, but in a whole new context, is going to be a challenge for Grimes.

Processing Yellowstone‘s ending was a “really bizarre transition,” after close to eight years working on it, but now “to go back into it in a new set of circumstances is going to be kind of transition” of its own, too.

“It will be weird,” Grimes says. “There’s going to be some familiar faces, but there’s going to be a lot of new faces too, so we’ll see how that all feels.”

Luke Grimes for High West’s “Protect the West” initiative.

All that he knows is that “nobody wanted it to be over” when Yellowstone came to an end last year. “I don’t think the fans wanted it to be over. A lot of us actors kind of didn’t want it to be over, and the studio and network certainly didn’t want it to be over.”

Grimes is further aligning himself with the love and protection of the outdoors that the hit series embodies through his partnership with High West’s “Protect the West” initiative, which supports charities nationwide working on land preservation and environmental stewardship.

“Every adventurer has their spot, that one place in the wild they cherish most. For me, this partnership with High West is about protecting those places before they’re gone,” he said in a statement. “The Protect the West initiative is something I deeply believe in, and I’m honored to lend my voice to the cause.”