In the words of actor Milo Ventimiglia, the This Is Us season finale is "definitely heartbreaking." Read ahead for a few spoilers from tonight's episode!

Last week, fans held their breath as a seemingly drunk Jack Pearson (played by Milo) drove off in his car to go save his marriage to Rebecca (Mandy Moore). Does he make it safely to her music gig two hours away? Or does he die in a devastating car accident? According to Entertainment Weekly, we'll find out in the Season 1 closer.

MORE: 'This Is Us' Star Mandy Moore Reveals Bad News About Jack's Death

Milo reveals that the episode will focus primarily on the couple viewers have loved since the start, including their lives before they began dating in the year 1972. A pre-mustached Jack returns home from fighting in Vietnam only to end up living with his parents. "That was a tough era for Vietnam vets — coming home from war, they weren’t welcomed with open arms,” the 39-year-old tells EW. “[Jack] comes home from a war and ultimately, quietly, there’s a bit of a war at home. It’s no surprise that Jack has had a bad relationship with his father, and that continues.”

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Milo with actor Jeremy Luke on This Is Us.

Meanwhile, Rebecca is struggling with her music career and pressures to settle down. "All of her girlfriends are married, the eye on their prize is meeting marriage material, and Rebecca’s eye is on her music that isn’t quite going the way that she was hoping," Milo explains.

But it's two scenes late in the episode that will resonate most with viewers, the actor shares. “They change the game of what the show is. They’re two incredibly impactful moments — one’s seeking conflict, and one’s seeking resolution. You may not completely disagree with the conflict, and you may not agree with the resolution, but they sit on complete opposite sides of one another.”

We're both excited and fearful! Tune into the season finale at 9 p.m. ET on NBC.