By Chloe Melas

CNN

(CNN) -- "This is Us" viewers may want to buckle their seat belts because stars of the emotionally volatile series are hinting at a bumpy season finale.

Susan Kelechi Watson, who plays Beth on NBC's hit family drama, said while her character has been prioritizing her husband Randall (Sterling K. Brown) in recent episodes, it will eventually strain their marriage.

"[Beth] took the position of being more sacrificial because of what was happening. This is a guy who for 36 years of his life has never known he had a real father somewhere, a biological father somewhere in the world," Watson told CNN at a recent press event. "I think it was time for her to take a step back and let him have that moment, especially since his father was dying. I think there's a time to...start those type of arguments and there's a time to say maybe you know what, maybe I'll just let him live and do what he needs to do and have his time, but pressure on a relationship is gonna happen."

Despite her suggestion of upcoming strife between the on-screen couple, Watson is confident their marriage will survive.

"We continue to choose each other, continue to choose to be in the relationship, continue to choose to love one another," she said. "There's definitely more conflict, but I feel like in my gut that they'll still choose each other."

For Justin Hartley's character, Kevin, his love life is complicated. He's in the midst of trying to win back his ex-wife and childhood sweetheart, Sophia.

"This is the love of his life. He's been in love with her since he was 10 years old and he made a horrible, horrible mistake [Kevin cheated on Sophia] and he's gonna take the time it's necessary to get her back," Hartley said.

Hartley also said he would "love" for viewers to see flashbacks of their marriage, and he's hoping that will happen with their storyline going forward.

Hartley also dropped a few details on Jack's (Milo Ventimiglia) pending death.

"There is a cliffhanger," Hartley said. "He didn't die an old man. He didn't live a long, long life ... it's sudden, it's unexpected, it's very tragic."

But, according to Ventimiglia, Jack will continue to appear on the show.

"Just because Jack is deceased doesn't mean that I'm not gonna be around or gonna be around any less," he said. "The last page for Jack may be his death but it doesn't mean there aren't more aspects to this man to explore and understand ... It doesn't mean I'm going anywhere.

"This Is Us" airs Tuesday night's on NBC.