Sound the alarm! Nicky Pearson has officially arrived on This Is Us.

According to Deadline, I'm Dying Up Here star Michael Angarano has been cast as Jack's (Milo Ventimiglia) little brother, who we believe died during the Vietnam War. Young Nicky was first introduced as a character early in Season 2 and as the season progressed, we saw more and more of his and Jack's relationship as we found out the severe impact Vietnam had on Jack.

Nicky's casting further confirms what we already know: When the show returns on Thursday, Sept. 25, it will dig deep into the Vietnam storyline and reveal just what tragedy caused Jack to lose his little brother. It's not only an important storyline for Jack, but for Kevin (Justin Hartley) as well; we know he is digging into his dad's past to help him find closure in the wake of Jack's death.

We Now Know When This Is UsSeason 3 Will Pick Up

To help make the Vietnam flashbacks feel more authentic, the writing staff has hired journalist and author Tim O'Brien, who's written a number of books related to his time in the Vietnam War, most notably The Things They Carried, as a consultant. That means you should prepare for some intense action coming into this season.

But if you're nose is still red from blowing your nose constantly, you'll be happy to know that Season 3 won't be totally heavy. The series, which is known for purposefully tugging at viewers' heartstrings, will lift things up by spending time with Jack and Rebecca (Mandy Moore) in their early courting days. Meanwhile, Kevin will be finding his way with his new love interest. So, maybe you won't need all the tissues this season.

This Is Us Season 3 premieres Tuesday, Sept. 25 on NBC at 9/8c.

Michael Angarano, <em>I'm Dying Up Here</em>Michael Angarano, I'm Dying Up Here