"This is Us" fans knew we'd be getting scenes of Jack (Milo Ventimiglia)'s stint in Vietnam in Season 3. Turns out those scenes won't be filmed on some Hollywood backlot, but actually on location in Vietnam.

Dan Fogelman, creator of the hit NBC series, told EW, "We’re taking it very seriously," of the decision to film in Vietnam.

We won't just be seeing Jack in action back in the day, but will follow son Kevin (Justin Harley), whom we last saw jetting off to Vietnam to learn more about his father's mysterious past.

And brace yourselves: We'll likely meet -- and lose -- Jack's brother Nicky (Michael Angarano), who we assume died in the war.

Fogelman said that the Vietnam story line will play out over the entire season, beginning with a special standalone episode about Jack in the military.

To ensure authenticity, "This Is Us" has brought on Vietnam veteran Tim O’Brien (whose books about the war include "The Things They Carried") as a consultant.

“We wanted to do the story right by Tim and vets and other people that have experienced Vietnam," said Fogelman. We’re taking it very seriously — in the same manner that we take seriously stories that involve weight, or anxiety, or miscarriages, or adoption."

Ventimiglia said that we're going to see things that "people really aren’t expecting. There is a lot of emotion in store for Jack Pearson, especially around war time, especially around his brother, and the circumstances that follow him home from war."

Hartley earlier told EW that going to Vietnam is "a healing thing for [Kevin] ... he's going to get a lot of information, some stuff that he didn't know and didn't expect. And it’s going to jar a few things."

Season 3 of "This Is Us" premieres Sept. 25 at 9 p.m. ET/PT.

[Via EW