'Yellowstone's Luke Grimes Says Monica Will Go Through 'Heavy Stuff' in Season 5 (Exclusive)

Things aren't going to be easy for the mom-to-be in season 5.

Luke Grimes is teasing trouble ahead for his onscreen love. ET's Rachel Smith spoke to the 38-year-old Yellowstone actor at Thursday's season 5 premiere in New York City, and he said that Kelsey Asbille's Monica will face the most drama this season.

"It's tough. I think the show, the whole thing is the drama. The whole thing is about how much can we put these people through?" Grimes, who stars as Monica's husband, Kayce, told ET. "I think, in this season, it's Monica for sure. She's going through some pretty heavy stuff."

While Asbille, 31, didn't tell ET about the challenges ahead for her character, she did say open up about Monica and Kayce's romance, calling it a "forever" kind of love. She also noted that the duo, who has one kid and another on the way, have been "fighting against all odds to be together."

"My goodness, they've had a wild ride," Asbille said.

The actors themselves have likewise been on a wild ride, one that both Grimes and Asbille are thrilled to be on.

"I love doing it. I love filming the show. I love being in Montana with all of these amazing people. That's the biggest perk. One hundred percent," Grimes said, with Asbille adding that "it's really exciting to be all together in New York and celebrating."

As for how long the duo will keep playing their respective characters, Asbille joked, "I've given her a lot of my 20s. We love these characters so much. I'll play her as long as I can."

"I wanna be Kayce, so I'd do it forever," Grimes agreed.

When it comes to what fans can expect from the show's fifth season, Grimes promised that the series "keeps getting better."

Season 5 of Yellowstone will premiere Nov. 13 on Paramount Network.