Don’t tell the lead actors out there battling for Emmy consideration, but we’ve got a little secret to share. It turns out that sometimes it’s their supporting co-stars who are actually the real reason viewers are obsessed with their programs.

Take, for instance, the legendary Rita Moreno who plays the feisty grandmother Lydia on Netflix’s “One Day at a Time,” a role that appeals to viewers of all ages.

“When people see it, they become a diehard fan,” Moreno says with a laugh. “But what absolutely amuses the hell out of me is that she’s the favorite character of many of the younger kids, which means teens and particularly even younger ones, which absolutely astonishes me. They just love Lydia.”

In the second go-around of the Gloria Calderon Kellett and Mike Royce reboot of Norman Lear’s ’70s sitcom, Lydia, a Cuban immigrant, gets her American citizenship and ends the season with a dramatic hospital scare. The show tapes before a live audience and Moreno says the directors who come on board are surprised that each episode often has at least one scene composed of 15 pages of dialogue.

“I don’t know how other shows do it, but it’s a lot and when you’re 86 it’s really a lot,” Moreno says. “Let me tell you, there are times when it’s really hairy for me. But I think to myself, ‘OK, you better work on this real hard over the weekend because this is not an easy scene. And you are 86, dearie.’ But, you know what? By the end of the season, I’m so alert it’s scary.”

In 2017 Nicole Kidman won an Emmy for lead actress in a limited series for her work as an abused wife on HBO’s “Big Little Lies.” This season she drew the audience’s attention in the supporting role of Julia, an intellectual who has an estranged relationship with her adopted teenage daughter in the acclaimed mystery-drama “Top of the Lake: China Girl.”

The Australian native has known series creator Jane Campion since she was 15, and they had previously worked together on 1997’s “The Portrait of a Lady.” Not surprisingly, that factor was a “huge attraction” for Kidman in ultimately taking the part.

“She had written the role for me and promised me a character role, which I love,” Kidman says. “It was a territory I had never entered before. To play this intellectual Australia woman who is in love with another woman and she leaves the man she adopted her daughter with, is wonderfully complicated. Just a ripe, rich character. And she was funny. Which I rarely get to be. Well, at least I thought she was.”

It’s hard to steal the show from five energetic and charismatic teenage kids, but David Harbour continued his stellar work as police chief Jim Hopper in the second season of “Stranger Things.” Harbour, who earned an Emmy nom last year for the role, sees Hopper as a man who will sacrifice everything in the name of justice. It’s one reason his character goes to extremes to keep the super-powered Eleven (Millie Bobby Brown) out of government hands.

“There’s a certain hardness in Hopper that I myself don’t have as much of, which is somewhat difficult for me to play. So, I was pleased that I was able to do that and that no one, from what I’ve heard, questions that relationship or what it was about,” Harbour says of Hopper and Eleven.

“There was just a rock-solid foundation. That was tricky line for me to ride as an actor, and I felt like I did accomplish that, so I was happy and proud of that.”

He also credits his performance to the creative culture of the Netflix series, noting, “I’ve never worked on a show where there’s been more freedom, more fun, more collaboration and more creativity. The fact that it’s so successful you’d think that come season two people would hunker down and be like, ‘OK, we have a formula, let’s not fuck it up.’ And instead, it’s just constantly taking risks.”

Alex Borstein’s road to playing fledgling comedy manager Susie Myerson, who takes on the title client in “The Marvelous Mrs. Maisel,” was truly unexpected. The veteran actress had just moved her family across the Atlantic and put her kids in school in Barcelona when she was asked to audition for Amy Sherman-Palladino’s pilot in New York.

“I had just made a decision to kind of leave and not really do any more on-camera stuff and then Amy sent me that script and I was like, ‘Goddammit. This is good. I gotta do this,’” she says.

As Susie, Borstein not only plays a character breaking down doors for a 1950s housewife with impressive standup comedy skills, the “marvelous” Midge (Rachel Brosnahan), but someone battling the inherent patriarchy of the entertainment world, particularly the comedy scene.

“Our show is hugely optimistic, which is rare right now,” Borstein says. “This little girl, Midge, is such a rubber-tree plant mover. High hopes and a big dreamer and to root for her, I feel like that might be a welcome respite from a lot of this. A lot of shows are just such downers. A lot of grit now. A lot of realism and a lot of reality.”

The only standout in this group who had the pressure of playing a real-life historical figure is Vanessa Kirby who portrayed Princess Margaret in “The Crown.” And her role is noted in the past tense, as creator Peter Morgan has stuck by his original plan to recast the series every two seasons. (In the third season, Oscar nominee Helena Bonham Carter will take over the role.)

Kirby admits part of her wanted to play Margaret during her unraveling later in life, but soon realized she was helping to chronicle a side of Queen Elizabeth II’s sister long forgotten.

“I knew that I had to sort of hold back because I felt like my job and obligation really was to really show up her young life,” Kirby says. “I’d heard so much about her, and in her later life she has been kind of a tragic figure; I was like, ‘People aren’t born tragic.’ And what happened to her in life so that she sort of hardened and became bitter or difficult or angry in a way?”

Kirby did a tremendous amount of research for the role, including speaking to ladies in waiting who knew Margaret in the ’50s and early ’60s when her portion of “The Crown” takes place. She says that she fell in love with Margaret and felt a duty to capture her essence at the time, especially considering she’d passed away in 2002.

“One of the ladies in waiting said that I was more Margaret than Margaret, which I can’t believe is possible,” Kirby says. “I’ve never told anyone that, but that was probably the nicest thing anyone said about it.”