Milo Ventimiglia Teases 'This Is Us' Vietnam Flashbacks, Courtship of Jack and Rebecca

The series patriarch died this past season, but as "This Is Us" tells its saga of the Pearson family across time, there is still plenty of story left for Ventimiglia's Jack. This season, the show's creators are planning to mine his character's past to carry his narrative forward.

That meant more makeup magic for the show's Emmy-nominated makeup team, who have already earned high praise for their work in aging Mandy Moore's Rebecca several decades. Now, they'll be turning back the clock for both Moore and Ventimiglia as they take a look at some of the formative moments of their lives.

"What we're doing this season is Jack goes back to Vietnam, and we explore kind of that younger Jack and what he experienced in war time," Ventimiglia told Jimmy Fallon. The show recently cast Michael Angarano (("I'm Dying Up Here," "The Knick," "Will & Grace," "Sky High") as his brother, Nicky, who fans already know goes to 'Nam with Jack.

Very little is known about Jack's relationship with his brother, so those flashbacks should prove enlightening, as well as informing Jack's behavior and possibly his ultimate struggles with alcoholism and addiction.

But it's not all sadness, as Ventimiglia was quick to point out. "On the positive side, we get to see Jack and Rebecca's budding love," he told Fallon. "You know, their courtship." That means first dates, doe eyes and perhaps the first of Jack's grand romantic gestures that Rebecca can never quite live up to.

Elsewhere in the interview, Ventimiglia shared a hilarious fan encounter at a gym after he'd been cast as bad boy Jess on "Gilmore Girls" and some of the wildest theories he heard about how Jack died, including one where he's an alien. Check it all out in the interview above.

Fans will have to wait until Sep. 25 for the Season 3 premiere of "This Is Us" on NBC.