'This Is Us': How Season 4's New Blind Character Changes Everything for the Pearsons

This is Us - Chrissy Metz as Kate, Chris Sullivan as Toby  - Publicity - Embed -2019
Ron Batzdorff/NBC

The season premiere of This Is Us might have been surprising for fans — the majority of the episode focused on three new characters who will soon become integral to the Pearson family's lives — but it was just as shocking for its stars. Chris Sullivan, who plays Kate's husband Toby and the father to newborn baby Jack (whose namesake, of course, is Milo Ventimiglia's late Jack Pearson), was floored by the revelation at the end of the premiere: that baby Jack was born blind, and the new 20-something character was actually Jack Damon all grown up.

"Reading that first script was a true shock — the way reading the pilot was," Sullivan told The Hollywood Reporter. "Our writers keep doing it over and over and over again. I was floored, once again floored by the This Is Us writers."

In addition to the complications of becoming new parents, Kate (Chrissy Metz) and Toby will also have to learn how to raise a son who is blind. Sullivan hasn't started doing any research about raising children without sight just yet, but doesn't actually plan to.

"I figured what will happen is I will learn along with the character as we go. It allows me to stumble my way through things I'm sure the way Toby and Kate will as well," he said. "But yeah, there will be a lot to learn."

In the meantime, the couple is happy that Jack is still a healthy baby boy — said Sullivan, "What else could you ask for?" — but they'll have to navigate their new normal.

"There's going to be a lot of learning," he said. "The learning curve is going to be steep. And they're going to have to figure a lot of things out on their own, because there's nobody they can go to for something like this. So it should be interesting."

That could put a wrench in Toby and Kate's relationship, creator Dan Fogelman told THR after the season premiere.

"They were not expecting everything that happened with Jack, and so that puts a natural exhaustion and strain on the relationship," said Fogelman.

But for now, Sullivan has faith in the couple: "They've been through a lot, so they're getting getting better at taking care of each other."

And while the actor who plays their adult son will return at some point — "It's a difficult period to go to all the time because we're pretty deep into the future and it presents production challenges, but we do plan on returning to it," Fogelman told reporters ahead of the premiere — the first part of the season will focus on the stories set in the present day.

In the meantime, know that Fogelman and co. are deeply impressed with Blake Stadnik, the experienced musical theater actor who plays grown-up Jack.

"Blake, when he came to us, was just clearly the guy," Fogelman said. "He had never acted on camera before. He had been a trained actor and he'd done a lot of musical theater and could sing, which was another massive quality that made this search impossible — we wanted to find an actor who could be a leading man and very handsome and very funny and look great with his bare ass on national television, but also be able to go stand in the Greek in front of a live audience and actually perform and sing a song. There were a lot of boxes to check. Blake's first day of shooting was literally lying completely naked in the bed and then having, like, a six-hour make-out scene with a young woman who was lovely opposite him. And then going on to the stage at the Greek in front of thousands of people during an intermission of a concert to perform a song. It was quite a trial by fire for him and he just blew us away in every possible way."

This Is Us airs Tuesdays at 9 p.m. on NBC.