In his initial conversation with Ann Napolitano about adapting her 2020 novel, “Dear Edward,” for television, Jason Katims made clear that among the changes he would need to make would be the creation of additional characters to help tell an ongoing story.

Of course, as the show debuted recently on Apple TV+, the titular character remains young Edward Adler, a brilliant home-schooled boy who also is a piano prodigy. Portrayed by 13-year-old Colin O’Brien, Edward is the lone survivor of a plane crash who is faced with a great deal of change very quickly and, understandably, struggles with all of it.

Other characters deeply affected by the crash lost loved ones who, like Edward’s parents and big brother, were on the flight.

One of the people invented for the series is Dee Dee Cameron, whose husband — and the father of her college-aged daughter — was among those killed. It’s more complicated than that, however, as shocking facts about the man’s life are revealed to her. As a result, over the 10 episodes of the season, Dee Dee must begin to chart a drastically new course for herself.

“I love this character of Dee Dee so much,” Katims says during a recent roundtable video interview. “She made me smile.”

She also made him think of an old friend, Connie Britton. The two worked together on the television version of “Friday Night Lights,” where Katims served as an executive producer and head writer and Britton portrayed Tami Taylor, the charming and supportive but also very strong-willed wife of high school football coach Eric Taylor (Kyle Chandler).

“When I thought of Connie playing Dee Dee ... I couldn’t think of anybody else in the world,” he says. “And it was an incredible experience working with her on it.”

And Britton was sure — well kinds, sorta, probably — that it would be.

“I was so happy to hear from him, and then I was like, ‘Well, I mean, it’s probably going to be like it was back then,” she says during a separate video interview. “But I don’t know we’ll see.”

She says they helped to create a wonderful working environment on “Friday Night Lights,” which ran for five seasons on NBC and later NBC and DirecTV’s 101 Network.

“Back in those days,” she says, “it was like, ‘Oh, this is how we want a show to be, so it was really fun to reunite with him and feel that again.”

On “Dear Edward,” Katims says, the two worked closely to develop Dee Dee.

“We had a lot of time before we started shooting, talking through the episodes, the scenes, (about) who this woman was,” he says.

Says Britton, “He had a general idea of who he wanted her to be, but then we were really able to talk through (it).

“Every role that I ever play,” continues Britton, whose TV credits also include “Nashville,” “American Horror Story” and the first season of “White Lotus,” with numerous movies on her resume, as well, “I want to make sure that there’s some kind of universal theme.

“We really were able to talk through what I wanted to make sure that we got to in terms of her own journey — so that we weren’t just seeing her in reaction to this horrible experience, this horrible loss that she has. And so we had great conversations about that. ... Underneath all the beautiful clothes and jewelry and the wealth, we were able to unravel who this woman really is and where she came from and in so doing, she actually finds her strength and power.”

Again, she is one of many characters viewers will get to know, mainly via meetings of an airline-funded grief group attended by several of the folks who lost someone in the crash.

Among the most compelling is Adriana Washington (Anna Uzele), an aide to a longtime U.S. congresswoman serving a district in New York City — who also happens to be Adriana’s grandmother. When the political icon dies in the crash, Adriana decides to run for her seat, but her ambitions are complicated when she grows close to Kojo (Idris Debrand), whose sister perished and who plans to take his young niece, Becks (Khloe Bruno), back to his native Ghana.

Then there’s Lacey Curtis (Taylor Schilling of “Orange Is the New Black”), who has had trouble having a child with her husband, John (Carter Hudson), which has caused great stress in the marriage. Suddenly, they are caring for Edward, who, as you would expect, is struggling greatly to adapt to so much change so quickly, despite making a friend in his neighbor Shay (Eva Ariel Binder), who has a much larger personality than he does.

Juggling myriad characters is nothing new for Katims. “Friday Night Lights” featured a large ensemble, as did a subsequent NBC series he created, “Parenthood.”

“He’s very adept at finding the ways that very diverse characters can overlap and still remain very specific individual humans,” Britton says. “Jason, I think, in an ensemble environment, is just masterful.”

The folks at Apple TV+ have asked the specifics of Dee Dee’s situation not be revealed, but know that hers is the kind of story you hear about now and then, as hard to believe this kind of thing may be.

“It’s such a hard thing to fathom — that something like that could happen,” says Britton, adding that she actually knows a woman who experienced something along the lines of what Dee Dee does. “I think that if I hadn’t ... know about that personally, it would have been even harder to play this.”

Penned and executive produced by folks including Katims and Cleveland playwright and “Draft Day” scribe Rajiv Joseph, the season of “Dear Edward” tells a pretty complete story, with all the key players in a different place — perhaps emotionally, physically or both — but the finale leaves the door open for a second-season order from Apple.

The guess here is that would be fine with the reunited pair, for whom the experience was similar to but also different from “Friday Night Lights.”

“We had this shorthand, but this character was nothing like Tami Taylor, so you never had the feeling of, ‘Oh, how do we differentiate this character?’” Katims says. “We talked about it a lot, and then the first moment we started shooting, (Britton) transformed into Dee Dee before my eyes,

“It’s just a dream to have that kind of experience. I was just in awe of her — am in awe of her.”