This Is Us premieres Sept. 20 at 10 p.m. ET on NBC

By Aurelie Corinthios
October 05, 2016 02:19 PM

The trailer alone is at 64 million Facebook views and counting, so we’re expecting big things from upcoming NBC dramedy This Is Us.

The series follows an ensemble of characters that initially share the same birthday but ultimately connect on deeper levels, and PEOPLE can exclusively reveal a First Look at Mandy Moore and Milo Ventimiglia‘s story line as Rebecca and Jack, a married couple expecting triplets.

“When you initially meet Jack and Rebecca in the pilot, their life is about to change exponentially,” explains Moore, 32.

As scenes of Moore and Ventimiglia in the delivery room unfold, the two actors reveal just how naturally their roles as costars came to them.

“Mandy is the kindest, most talented, most beautiful soul I’ve come across in a long time,” says Ventimiglia, 39. “When we shot the pilot, the funny thing was we didn’t really know each other, but we had this immediate connection.”

“As an actor, it’s obviously our job to find chemistry with somebody who is playing our spouse or boyfriend or girlfriend or whatever,” adds Moore. “Every now and then, you luck out and that chemistry is just palpable and it’s right on the surface. And I really lucked out with Milo.”

“These are two deeply connected people,” she continues. “They have a soulful connection, and a deep kinetic, sort of love.”

Promises Ventimiglia: “If you’re not already already in love with Mandy Moore, you are going to fall head over heels in love with her from this show.”

Throughout the course of the premiere episode, Moore’s character Rebecca goes into labor – but the delivery takes a turn, and the couple ends up losing one of their triplets.

“I would imagine that it sort of brings them closer than ever, but their lives are going to be sort of forever marked by this experience,” says Moore.

As for what drew her to the role? The idea of playing a wife and a mother – which marks a first for the actress.

“I’ve never done that, and I feel lucky to be portraying the matriarch of this family,” says Moore. “These two individuals set the tone as we move forward in the show.”

This Is Us premieres Sept. 20 at 10 p.m. ET on NBC.