Mandy Moore Revealed A 'This Is Us' Season 3 Premiere Spoiler That Will Leave You Nervous

It's a series known for equally potent shock and aww moments, and Mandy Moore's newest This Is Us Season 3 preview indicates that the Pearson family roller-coaster ride will be taking an abrupt turn right from the jump. "There's something that doesn't involve my character that's a bit of a twist in the first episode that people are going to be like, 'Whaaa…?'" the actor teased during an interview with Entertainment Weekly, published on Friday, Sept. 21.

Loyal This Is Us viewers have rightfully learned to expect the unexpected, but Moore said their is no way to prepare — and also offered a possible warning. "It's a bad 'Whaaa…?' It’s not heartwarming," she added. "People are going to be like, 'Whaaa…? Why? How? What?' At least I was, and I knew that it was coming, but still, when you read it, you're like, "No. Whaaa…?" so that's pretty interesting."

Anyone who's even casually watched the NBC hit will surely have a box of tissue at the ready when Season 3 premieres on Tuesday, Sept. 25 at 8 p.m. ET, regardless. But this new shocker could very well be the thing that made Moore and onscreen daughter Chrissy Metz cry upon reading the episode's script, with the former cautioning fans via Instagram that the new This Is Us chapter is "NOT for the faint of heart."

Given that in the next breath of Moore's EW interview she mentioned Randall's Season 2 finale flash-forward shocker, there's a distinct possibility that this new plot-line could be part of the episode's big reveal. To recap: In the one of the finale's concluding moments, a salt-and-pepper-haired Randall (played by Emmy winner Sterling K. Brown) cryptically tells adult Tess (younger Tess doppelganger Iantha Richardson), "It's time to go see her." After his daughter replies, "I'm not ready," he agrees, adding, "I'm not either." Cue an abundance of fan anxiety.

"I think that every episode is offering a more fully realized picture of who that is," Moore added to EW. "It's not being dragged for the sake of being cheeky. I think it's just really brilliant storytelling."

For his part, Brown has promised that fans will find out who the "her" is at some point this season. As he recently told EW, "It is someone that we have met over the first two seasons ... so it won't come out of nowhere." Echoing Moore's sentiments, Brown added that "it's probably not what you suspect ... it will be like, 'Oh, wow — didn't see that coming.'" (Worried viewers did get some minor solace, however, after Susan Kelechi Watson revealed this summer that her character Beth Pearson will not die this season.)

Striking This Is Us' true-to-form balance, however, Moore further told EW that Season 3 will include "some of the levity, and the lightness, and the sweetness, and the romanticism" of "the journey of young coupledom" for Rebecca and husband Jack. Of course, fans have already gotten a sneak peek of Jack and Rebecca's first date at a carnival, where in one truly sweet moment, the Pearson patriarch wipes a piece of candy apple off his future wife's lip.

Even so, "that is juxtaposed with starting life over at square one again three months post-Jack passing," added Moore in her interview with EW. "You bounce right back into the months post-Jack's death, and that is just, ugh. It's a s—show at home, and everybody is off the rails. Life is not going smoothly. Everything's falling apart."

Saying hello from the other side of Jack's heartbreaking death (which had been teased since the tearfest's debut season) hasn't exactly been a weight lifted for Moore — on or off screen, though. As she explained to EW:

"Playing the shock of losing somebody, you want to get to that point where you feel it and you are on the verge of tears, but then you pull back from it, so all day sitting in that kind of frame of mind is like blehhhhhhh. It's awful. It's almost more daunting than playing the pain of losing someone. That’s been a surprise to me…it's not something that you can just pop out of, and not to say that the other is either. You're in that world, and you're sitting in that emotional stew all day, and you just have the pot on "simmer," so you're like, "Okay, cool. I got to turn it up to high heat now because we're ready to shoot.” With this, it’s like turning it up to almost high heat and then backing it down a little bit because you’re not in the throes of that abject grief anymore, but it is your constant companion. It hasn't left you, and it won't leave you for a good amount of time."

Moore's grief analogy may give fans some minor Crock-Pot-related PTSD, but she still promises that "this is the best season yet!" While viewers will have just a bit longer to wait to make that assessment, her latest comments, however, leave little doubt that an explosive, new shocker is imminent.