This Is Us” is following its three-episode deep-dive into “The Big Three” characters in its second season with three special episodes devoted to key Pearson spouses in the third season. Toby (Chris Sullivan), Beth (Susan Kelechi Watson) and Miguel (Jon Huertas) will all receive such standalone episodes.

Co-showrunners Isaac Aptaker and Elizabeth Berger acknowledge characters such as Toby and Miguel have been polarizing to some of their audience. However, they were keen to explore more of their backstories and relationships with the various members of the Pearson clan as a way to hopefully change some minds about them.

“Jon Huertas is the charming-est, coolest guy and such a good actor, but has such an uphill battle to make America fall in love with this character,” Aptaker said during a pop-up fall preview event held by the show’s Canadian broadcaster CTV. “But we do think getting to see a bit more of his story this year, people are going to start realizing what a good guy he is and what a support he is to the Pearson family in the wake of Jack’s death.”

“It’s always so interesting to us that people respond the way they do,” added Berger. With Toby, she said, dislike “comes out of a deep love and a fierce protectiveness that people feel for Kate, which I completely understand, but I think they’re so with her that any slight thing that Toby does, they’re watching under a microscope.” Berger believes Toby is “a flawed but wonderful partner” and said audiences will get to see even more of that in the third season.

In the Toby-centric episode, “This Is Us” will feature younger version of the character to explore some of his past, which should shed a light on his present-day struggle with depression that factors heavily into the third season. The show is also bringing back his parents, played by Dan Lauria and Wendie Malick.

Lauria, whose casting in the series was announced early on in the second season, was originally tapped to play Jack’s (Milo Ventimiglia) sponsor, the pair confirmed. But that scene was cut and Lauria (who worked with creator Dan Fogelman on the short-lived Fox series “Pitch”) was later recast into this more significant, recurring role.

“We love Dan and we’re massive ‘Wonder Years’ fans and just huge Dan Lauria fans in general so we knew we wanted to find something for him,” Aptaker said. “He is actually friends with Chris Sullivan from the New York theater world. And Dan and Wendie are also really close, they perform a play together about 9/11. So it was sort of Sulli’s dream that Wendie and Dan would play his parents. It worked out perfectly that we couldn’t fit Dan in as Jack’s sponsor role because he got an even better part.”

And speaking of Jack, the third season, which is diving into his time fighting in Vietnam, under the guidance of author Tim O’Brien (“The Things They Carried”), will actually film some of those sequences overseas. “The scope of it is just incredible for a network TV show, the amount of world building that we’re doing,” Aptaker said, noting that they also built part of Vietnam in Los Angeles, Calif. “It looks like a movie.”

“It’s not political, it’s part of our history,” creator Dan Fogelman told Variety of the approach to the storyline. “Jack was always going to be a man that everybody loves and he’s this amazing father, but he also harbors some secrets. [We] established him, learned his life as a father, saw how he passed away, and [now go] back in time and learn what had formed him.”

And in doing so, the audience will also learn about Jack’s brother Nicky (Michael Angarano), who Fogelman said “is going to be something people are talking about quite a bit this season.”

“He’s Jack, but he’s different than Jack and his relationship with Jack especially in the past and in Vietnam is something that is very exciting for this season,” Fogelman said.

“This Is Us” season 3 premieres Sept. 25 on NBC.

Margeaux Sippell contributed to this story.