The inevitable demise of one of TV's most unforgettable moms left viewers grasping for tissues Monday night.

This is the episode that made actress Mandy Moore throw up after reading the script.

Rebecca Pearson, played by Moore, met an emotional end on the hit TV show "This Is Us." In the show, Moore portrayed the matriarch of the Pearson family. Her character had Alzheimer's, which she'd battled for quite some time on the show.

Emotions ran high between viewers and the cast as the second to last episode, aptly titled "The Train," brought back familiar faces. Faces like her second husband Miguel (John Huertas) and Dr. K (Gerald McRaney).

Rebecca's life plays out through the metaphor of her making her way through a train as her younger self, guided by her son Randall's (Sterling K. Brown) late biological father, William (Ron Cephas Jones). As her condition worsens, and her family gathers around her to reminisce on her life, she sees the stories that her sons Randall and Kevin (Justin Hartley) tell, come to life.

Just as she reaches the end of the train, her daughter, Kate (Chrissy Metz), rushes to her bedside, joining her brothers in bidding a tearful farewell to their beloved mother. After hearing her daughter's voice, she reaches the caboose, where she lies down in a bed. Beside her is her late first husband Jack (Milo Ventimiglia), and they mutter a single, yet heavy "hey" to one another.

Before the episode aired, Moore spoke with Entertainment Weekly to discuss the emotional episode.

She told EW:

"I think the simplicity of what's in store for people in parts of this episode are what the whole series is really about. People waiting for things to be tied up perfectly in a bow with every single character and every single story need to abandon that idea because that's not the reality of life anyway."

The final episode of "This Is Us" is set to air May 24th on NBC at 9 p.m.