Luke Grimes was "hesitant" about starring in the Yellowstone spin-off Marshals.

The 42-year-old actor reprises the role of Kayce Dutton in the new CBS series but revealed that he was concerned about ruining his alter ego's "perfect ending" in the original Western drama.

Speaking to Extra, Luke said: "I was kind of hesitant because I just loved the way that Kayce's story ended in the original show... It was a perfect ending and he got everything he'd been fighting for, which is a much simpler light out from under the weight of all these things that has been in his family for years, and he got his life and with his family."

However, the Fifty Shades of Grey actor revealed that he was intrigued by the prospect of exploring Kayce's past with the US Navy SEALs in Marshals.

Luke said: "I thought, in a way, that opens up the world for a lot more story. And, you know, I'd meet a lot of fans that would be like, 'Man, we kind of would love to go into Kayce's backstory with being in the SEALs.'

"It's like a really cool thing we never really touched on, you know, he's special operations, and in this show, we get to really dive into that. So that was also something where I was like, that could be a lot of fun."

Grimes teased that fans will see his character evolve in the new series.

The star explained: "He's not Mr. Personality because of what he's dealing with because of his past. I think what's cool about this show is through this new purpose he has and being able to use that skill set for something good, he sort of starts to heal himself and come out of his shell a little more."

Luke added of Kayce: "He's an honest guy and he's honest about his feelings and he wears his heart on his sleeve... He's never tried to be a tough guy."

Yellowstone was rocked by the abrupt departure of Kevin Costner - who played the role of John Dutton III - midway through the final season in 2024 but Grimes explained that he tried to take a philosophical approach to the situation.

He told Men's Health magazine: "None of us saw it coming the way it did, and obviously there was news about possible blowups behind the scenes or whatever. But just like in life, man, these things happen, they happen fast, and they're not predictable.

"I lost my father a few years ago. It happened fast, and it was not the way that you would think that that would happen. In life, these things happen and then people have to start making decisions. And in our little Yellowstone world, that helped ramp the show up into a boil."