Emma Thompson plays Katherine Newbury in “Late Night.” (Emily Aragones/Amazon Studios/AP)

It remains unbelievable: No woman currently hosts a nightly talk show on network television. And since Joan Rivers broke the glass ceiling in 1986 on Fox, only a handful of women have followed in her footsteps.

That’s why the actor Emma Thompson has called her latest film, “Late Night,” out Friday, a work of “science fiction.” It imagines a world in which one of the icons of late-night TV is a woman who has been on the air for nearly three decades. Thompson plays Katherine Newbury, a hard-driving boss whose concern is not getting a show but staying relevant as popular culture threatens to leave her behind.

Nightly talk shows symbolize how resistant the entertainment industry can be to change. They have been fixtures in American pop culture since the earliest days of television, with few updates to the format over the years. And yet the hosts hold coveted positions — within networks and in our collective psyche.

“It’s just such an intimate role that the late-night talk show host plays in our lives,” Mindy Kaling, the writer of “Late Night,” told The Washington Post. “We’re usually watching them in bed before we go to sleep, and the things they talk about, the way they make jokes, that’s the last thing we think about. It’s a really intimate relationship, and it’s a really powerful one.”

Kaling says she’s been obsessed with late-night TV since she was a kid. As research for writing “Late Night,” she pored over Bill Carter’s books about the genre and interviewed writers from most of the major shows. She was fascinated by beloved stars who seem so familiar to viewers but who have vastly different off-screen personas.

To write a female host into the center of a late-night show, Kaling had to depart from history. “Late Night” is not intended as a polemic against the maleness of today’s talk shows; the current crop of hosts are “doing an excellent job,” says Kaling, “particularly in this political climate.” She just wanted the lead in her comedy to be a woman.

“I didn’t think that our culture needed me, Mindy Kaling, to be writing this juicy of a comedy role, a lead comedy role for a man right now,” she said.

Still, Kaling’s choice of writing her female lead as the host of a late-night show feels radical. Watching Thompson’s Katherine deliver monologues and interview guests underscores how few real-life women have done the same. The list is short. Busy Philipps, Robin Thede, Chelsea Handler, Kathy Griffin and Mo’Nique have hosted now-canceled late-night shows on cable. Wanda Sykes had a short-lived Saturday night show on Fox. Samantha Bee currently stands as the lone woman on late night, with her politically charged “Full Frontal” running weekly on TBS. (In September, Lilly Singh will take over Carson Daly’s 1:35 a.m. weeknight slot on NBC — making her the first woman to host a nightly network talk show since Rivers more than 30 years ago.)

Meanwhile, the number of men in late night has only grown, as more shows have been added to the airwaves. In 2015, as Bee visited a pumpkin patch with her family, she saw a Vanity Fair cover about the titans of the late-night boom. The image featured 10 men and had omitted her.

So, Bee tweeted back an altered version of the cover that included her as a centaur with lasers shooting from her eyes.

“I got so mad I literally sat over by the cider donuts and sent that tweet,” she told the Daily Beast in 2015. “I was like, ‘I WON’T BE IGNORED!’ ”

Philipps, who until recently hosted a show on E!, says she has “always been conscious” of the dearth of women on late-night TV. “In fact, when I decided that this was something that I wanted to do and pursue, almost my entire motivation in adamantly demanding that I do a four-night-a-week late-night show was because there are no women who have that,” she says. “There is a space for having pop-culture and entertainment conversations that are led by women, as opposed to men.”

It’s unclear what we’ve missed out on by not having more women in those roles, Philipps says. The kings of late night didn’t just entertain regular viewers before bedtime; they inspired generations of comedians. “So, we’re talking about generations of women who didn’t have that, didn’t sit at home in front of the television and wait up to see so-and-so,” she said. “There is a real missed opportunity in cultivating and inspiring generations of women writers and comedians.”

Mo’Nique wanted to have a talk show since she first saw Oprah doing it on a local station in Baltimore. “That was the first time I had seen somebody that looked like me” in that role, Mo’Nique said. “Well, damn,” she remembers thinking, “that’s possible.”

“The Mo’Nique Show” ran between 2009 and 2011 on BET. The host ended every show by encouraging viewers to essentially hug themselves good night. “We wanted it to be very nurturing,” she says. “It was the best time of my career because I was a little girl walking in my dream.”

But behind the scenes, it could be tumultuous, Mo’Nique says, with disputes over pay and the need to deal with the kind of heightened scrutiny that many women in entertainment encounter. “To be a woman in late night, they might question a bun that you wear on your hair,” Mo’Nique says. “I don’t know if Seth [Meyers] or one of the other babies in late night have ever been questioned about their wardrobe or their hair.”

But Katherine Newbury is not the character in “Late Night” who faces the challenges that come with being an outsider in the world of late-night television. In fact, Newbury is the old-timer who faces criticism for not supporting diversity in late night; her writing staff is made up of white men. And so, somewhat impulsively, she hires a woman of color — played by Kaling.

It’s a nod to a different dimension of homogeneity in the industry, an acknowledgment that the person on camera isn’t the only one who matters. According to a recent Los Angeles Times analysis, the percentage of women who make up late-night TV writing staffs hovers between 17 and 45 percent. In a reoccurring segment on “Late Night With Seth Meyers,” writers Amber Ruffin, a black woman, and Jenny Hagel, a gay woman, deliver punchlines that would be weird coming from Meyers, who is a straight white man. It’s called “Jokes Seth Can’t Tell.”

The segment is a good example of Meyers using his privilege to pass the mic to writers whose voices have been underrepresented in late night. And yet Meyers still has the desk, and may keep it for a while. Diversifying the network late-night shows can be slow going, especially if the current hosts are considered successes.

Elsewhere on the small screen, however, women are thriving, Kaling notes. Since she started her own TV show, “The Mindy Project,” in 2012, television has been flooded with more comedies fronted by women.

"What I am happy about is that, when you watch the movie, no one has come out of it feeling that the experience of seeing [Katherine] was strange,” Kaling says. “It becomes very obvious that that would be a very natural choice and that Americans would respond to that.”

The “science fiction” of it all doesn’t come from the implausibility of Katherine Newbury. It comes from the fact that she is perfectly plausible, and yet she doesn’t exist.

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