Find Out the Special Code Word the This Is Us Cast Used for Jack's Big Death Reveal

After months of unending speculation, the shocking This Is Us season 2 premiere finally gave fans one big clue about how Jack died — and keeping it a secret was no easy task.

At the very end of the Sept. 26 premiere, a flashback showed an emotional Rebecca (Mandy Moore) pulling to their family home, which was left in charred remains — leaving viewers to assume that everyone’s favorite TV dad Jack (Milo Ventimiglia) likely died in a fire.

During an appearance on the Today show Tuesday, Moore, 33, revealed how the cast and crew of the beloved NBC series kept the big reveal under wraps by using a special code word.

“I hope Dan Fogelman’s okay with it!” she told Hoda Kotb and Savannah Guthrie. “We called it ‘the marble.’ It was like, ‘So then when the marble happens…’ Listen, we’ve all been holding onto this secret for a year and a half now.”

But that wasn’t the only trick they used — Moore said they built the charred house about an hour and a half outside of Los Angeles and edited the usual This Is Us set signs to “throw people off in case someone was being followed to set.”

“I have never been a part of something like this before,” she said with a laugh.

Of course, we still don’t know how the house burned down, or any specifics about Jack’s death, and Moore admitted the secrecy of the show can be a challenge, even for its stars.

“I feel like I have the best job because I get to portray this character from age 22 to 67 and everything in between,” she said. “But it’s overwhelming at times, because obviously, as an actor, you want to have all of the answers and know the life that’s been lived … and I don’t have all the answers.”

This Is Us airs Tuesdays (9 p.m. ET) on NBC.