'This Is Us' Cast Teases Tearjerker Season 3 Premiere: 'Not for the Faint of Heart'

The season three premiere of This Is Us has already been written, and Mandy Moore and Chrissy Metz [...]

The season three premiere of This Is Us has already been written, and Mandy Moore and Chrissy Metz dropped little teasers about the upcoming new episode.

While on a plane to Paris, Moore said she just finished reading the script for the premiere, then watched an episode of Queer Eye, which was not a good idea.

"Reading the first episode of [This Is Us] season 3, followed by [Queer Eye] is NOT for the faint of heart," the 34-year-old wrote on her Instagram Story, with a selfie from the plane.

(Photo: Instagram / @mandymooremm)

The 37-year-old Metz also read the new script on a plane, but she was heading home. The story made her cry so much that a flight attendant asked her if she was OK.

"Just read our season 3 premiere episode on the flight home... The flight attendant asked if I was okay... still not sure," Metz wrote, alongside a photo of herself with co-star Chris Sullivan singing. Metz also included a GIF of a young boy with the text "Feelings."

(Photo: Instagram / @chrissymetz)

Roxy Olin, the daughter of director Ken Olin and a staffer on This Is Us, also teased the first page of the script, reports Entertainment Tonight. She blocked out the episode title, but revealed it was written by creator Dan Fogelman with showrunners Isaac Aptaker and Elizabeth Berger. The episode will be directed by Ken Olin, who has directed 11 episodes of the series, including the season two finale, "The Wedding." He will also serve as an executive producer on the series.

In May, Moore and Fogelman said parts of the series finale have already been filmed, even though he is not sure how many seasons the show will run.

"We're pretty far out. We know where it ends and we know the path for each season," Fogelman said at a "for your consideration" panel on May 29. "We've always had a plan, we didn't want to get stuck … The show won't overstay its welcome, we have a story to tell, we want to do this the right way. I've actually already shot pieces of the final scene of the series."

Moore, who plays Rebecca Pearson, played coy when asked if she could give more details on the finale already being shot.

"I don't know!" Moore told Entertainment Tonight. "Maybe parts of the ending have been shot!"

Now that we know how Jack (Milo Ventimiglia) died, the biggest mystery heading into the season is who the "her" Randall (Sterling K. Brown) is talking about in a flash-forward scene with a grown-up Tess (Iantha Richardson).

"This is what I can tell you: The show kind of knows where it ends, and future Randall [in the scene in question] is sort of in a place [that occurs] towards the end of the show," Brown told Entertainment Tonight in May. "I can't say any more than that."

This Is Us will be back on NBC on Tuesday, Sept. 25. By then, we should all be stocked up on tissues to prepare.

Photo credit: Ron Batzdorff/NBC