'This Is Us' Star Says Jack Is Hiding a Very Big Secret

(Warning: This article contains spoilers for the newest episode of This Is Us)

This week's episode of This Is Us dove a little more into Jack's backstory, showing viewers how he beat his alcohol addiction when the kids were younger. However, if This Is Us superfans were paying close attention, the episode also revealed that Jack hasn't been totally honest about his past.

Toward the end of the episode, as Kate was singing in her first real gig, Jack was shown hitting the punching bag in an effort to get past his alcoholism. The scene also included a small flashback to Jack as a young man, where he's seen getting out of a helicopter with an assault rifle in Vietnam.

If you recall, back in the first season, Jack told Mrs. Peabody that he was only a mechanic in the war. This flashback proves that wasn't exactly the case.

While speaking with EW, This Is Us star Milo Ventimiglia said that Jack was definitely keeping some of his past to himself.

“Jack is holding onto a lot,” Ventimiglia said. “Anyone who is in the theater of war is experiencing things that a civilian on the streets has no idea about. War is horrible, and if you’re right there in the middle of it to see the atrocities, you can’t not be impacted by it."

"So only getting a glimpse of Jack hopping out of a helicopter with an M16 rifle, looking like he’s in the s***, he wasn’t just a mechanic. Or he was just a mechanic. But also, I think Jack in his younger years saying he was just a mechanic is just a way to put off other questions, because Jack had adjusted his own perspective on life post-war and moved forward. And man, that’s just God-given grace if anything. It’s nothing anyone can ever expect to have, but Jack was fortunate enough to have a clean perspective moving forward and manage whatever emotional distress he experienced while he was over in Vietnam,” he added.

As Ventimiglia continued, he confirmed that fans would be seeing a bit more of Jack's time in Vietnam as the season goes along.

“We’ve heard about it, but now we actually get a glimpse of it,” Ventimiglia stated. “We’re ultimately going to spend some time in that world understanding what had gone on there. I won’t say for certain when it will happen, but knowing that we’ve caught a glimpse of Jack and especially as he’s wailing away on a bag trying to beat the demons that are bubbling up from underneath, his father’s drinking, the things that are making him want to break bad — that’s part of it. That’s a side of Jack that we’re going to know a lot about and spend some time with.”

This Is Us airs new episodes on Tuesday nights at 8 p.m. ET on NBC.