Since This Is Us first premiered in September, we’ve dedicated our Tuesday nights to watching the multi-generational Pearson family navigate life. We’ve laughed, we’ve cried, and we’ve grown so attached to the characters at the show’s core that their ups and downs feel much like our own. But while plenty of plot twists have brought on the tears, nothing has torn us up quite like waiting to learn more about the tragic fate of the family’s patriarch, Jack (played by Milo Ventimiglia).

In episode one, we found out that Jack isn’t alive in the present-day timeline. Since then, the show has repeatedly reminded us of the fact that Jack is dead, revealing where his ashes remain and even offering up a quick and depressing glimpse at his funeral. Even so, we have yet to discover what actually leads to Jack’s demise, and much like his daughter Kate (Chrissy Metz) isn’t ready to tell her fiancé what happened to her father, we aren’t quite ready to learn the sad and final truth. But with just two episodes left this season, we’re likely to get some answers—and soon.

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Last week, the show’s star Justin Hartley (who plays Jack’s son, Kevin) stopped by InStyle to talk all things This Is Us. During his visit, Hartley revealed that he’s already privy to the truth behind Jack’s passing. “I do know what happens,” Hartley said, breaking out in a grin. “And I shouldn't be smiling because it's not funny, but I like the fact that I know and no one else does.”

While he’s not spilling any secrets related to the big storyline just yet, Hartley is adamant that it’s in the best interest of the show’s fans to wait it out. “I would tell you if I thought you truly wanted to know, but you don't want to know,” he said. “It'll spoil it, and I don't want to do that to you. I love you all too much to give you that information. When you do find out, you'll be happy that no one ruined it—and if someone does spoil it for you, you can de-friend them.”

As for what we can expect from the big reveal when it happens? “It's tragic,” said Hartley. “You see how it affects all of the characters in their own way, and it explains a lot about the relationships. Man, it's heavy. It's really, really heavy.”

Scroll down for more of our chat with Hartley, including what’s next for his character and what to expect before the season finale.

Last we saw Kevin, he was about to take the stage for opening night of his play but ran out to help his distressed brother, Randall. Where do we find him when the show returns?

Kevin has to figure out how to get those seats filled again in the theater because he kind of left everybody. His whole family showed up for his play and he was the only one that didn't show up. He's got to figure out how to get that back together and how to get the theater critic back in the theater to watch the play. Kevin thinks that the play is really good and that it could be a great vehicle for him in his career, but his brother needed him. It's fun to see how he's growing and becoming a man right before everybody's eyes.

We were all shocked when Kevin showed up on Sophie’s doorstep to proclaim his feelings for her, since we hadn’t met her before and he had just been in the middle of a love triangle with two other women. How did you react when that script landed in your lap?

I thought it was perfect that Kevin, of all people, has been in love with the same girl since he was ten years old. You think he's gonna pick between these two women in his life and then you realize it's not really a different girl that he chooses, it's been the same girl the whole time. I thought that was very, very, Kevin of him. He's really a romantic guy; he's his father's son.

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Will they end up together?

I hope so. I’m rooting for 'em. I think he's got a lot of patchwork to do. He needs to win back Sophie's trust and prove himself to her all over again, but I think he's willing to do that and put in the time and effort. I really hope it works out for them.

The show’s last episode focused on Randall’s relationship with his biological father, and it was an emotional rollercoaster. What were your thoughts when you saw it?

Oh, it was such a special one. Our show does a really good job of storytelling, and the way in which we tell the story is unique, being that it's multigenerational. And then we do these standalone episodes where there's a specific topic or a story that needs an ample amount of time to tell it properly, and that was one of those episodes.

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A few actors on the show play younger versions of Kevin as he's growing up. What's that like for you?

I love it! I think they do a fantastic job, and they make my job a little easier. They're telling the backstory, which is so cool. Obviously, I don't get to work with them because that would be a little weird—they’re basically on a different show. But I love those guys.

Do they look like you did when you were younger?

You know, they actually don’t. But at the same time, I think when you put us all together, you can see how we look like we're family. My fiancée, Chrishell, took a picture of us all three of us together at the wrap party, and I guess we look like we could be the same person. They're much better looking than I am, though.