The beloved author of children’s books is experimenting with new forms, alongside starry collaborators, at the Kennedy Center.WASHINGTON — Do you know the words to the Queen of the Night’s stratospheric showcase from “The Magic Flute”? Maybe the Duke’s famous tune from “Rigoletto”? Carmen’s Habanera?No, not those words. The other ones: the words, at least, as they are now known to my 6-year-old daughter and the hundreds of children who took grown-ups like me to the Kennedy Center here recently for the premiere of “The Ice Cream Truck Is Broken! & Other Emotional Arias,” an experiment, including a short new work by the composer Carlos Simon, in what it might mean to draw a very young and impossibly demanding audience into a life in opera.See, you might think that Carmen is relating her views on love, but no. Listen closely, and you’ll find that the singer should have shared her cotton candy with her friends, and absolutely will … tomorrow. “La donna è mobile”? That’s about how milk squirts out your nose if you happen to laugh at exactly the wrong time. The Queen’s aria? That’s still about anger, but it now invokes something far worse than the vengeance of hell.“This bicycle,” it begins, in a fit of preschool pique, “is such a poo-poo vehicle.”The director Felicia Curry, left, with Willems during a rehearsal for “Don’t Let the Pigeon Sing Up Late!,” a short new opera created with the composer Carlos Simon.Lexey Swall for The New York TimesWillems and Simon reunited after their first opera effort, “SLOPERA!,” also at the Kennedy Center.Lexey Swall for The New York TimesOpera’s great composers have a new librettist, and he is almost certainly the only person who could induce an institution like the Kennedy Center to do something like this, let alone get Renée Fleming to join him in hosting it; inspire a quintet of young singers to ham their way through it; and persuade Simon, one of the busiest composers around, to crown the show with a 20-minute piece that gives an attention-seeking, picture-book Pigeon the prima donna spotlight it has surely always craved.The writer for it all? Mo Willems, who, it turns out, really loves opera!“The commonalities between what my industry, or my main industry, does and what opera does are incredible,” said Willems, a six-time Emmy Award-winning former Sesame Street writer, who has earned three Caldecott Honors for picture books and reigns as a near-deity in children’s literature.“It’s big emotions,” he added during an interview at the Kennedy Center before the premiere. “It’s direct communication. It’s interior dialogue. It’s self-discovery. And both forms really have been pushed off to the side of the mainstream, and I think that they have more power that way.”WILLEMS HAS ALWAYS BEEN a broader artist than just a writer of picture books, though that task alone is such that he calls it “as easy as describing the history of Byzantium in three words.” Some of his most celebrated characters — who include a venturesome plushie called Knuffle Bunny, the on-and-off best friends Elephant and Piggie, and that insatiable, inimitable Pigeon — had already starred in musicals that he had written before he formalized his long association with the Kennedy Center in 2019, when he became its education artist in residence. That three-year position coincided with the pandemic, to which he responded with invaluable “Lunch Doodles” videos, but it still let him explore a range of genres, including symphonic music, which he said “has always been important to me.”“Beethoven’s Fifth is the easiest example,” he explained, “but it’s basically the arc of an episode of television, or a movie: ‘Ba-ba-ba-baaam,’ oh, it’s exciting — and then you take the theme, you take the theme, and then you build with it. So when I was writing a show called ‘Codename: Kids Next Door,’ which is a silly sort of action comedy, I would literally write to the symphony.”Siphokazi Molteno, left, during a rehearsal for “Don’t Let the Pigeon Sing Up Late!”Lexey Swall for The New York TimesA rehearsal for “Don’t Let the Pigeon Sing Up Late!,” which is based on Willems’s book “Don’t Let the Pigeon Stay Up Late!”Lexey Swall for The New York TimesFor the National Symphony Orchestra, Willems painted giant abstractions to accompany a cycle of Beethoven’s nine symphonies, and he worked with the musician Ben Folds to adapt one of his books, “Goldilocks and the Three Dinosaurs,” for the concert hall. Hearing plans for “Goldilocks” led Tim O’Leary, the general director of the Washington National Opera and a Willems-reading father of three, to inquire about a commission.At their first meeting, Willems was “feigning ignorance” about opera, O’Leary recalled, but the author quickly sent him a copy of an Elephant and Piggie book — “I Really Like Slop!” — with the inscription “Tim, this book really sings.” By their second encounter, Willems had the libretto in his head, a sketch of the characters in concert dress and a title: “SLOPERA!”“Obviously, once it was called the ‘SLOPERA!’ we had to do it,” O’Leary said.Willems says that opera is similar to picture books in that in both cases, the text cannot stand on its own.Lexey Swall for The New York Times“SLOPERA!” could only be performed live outdoors on account of the pandemic, but an indoor recording, with piano accompaniment, was shown virtually to more than 300,000 schoolchildren.” Piggie gets Gerald the Elephant to try slop, a stinky green delicacy among porcine foodies. He does, after his initial refusals upset his companion, and he endures the consequences in something like a bel canto mad (or death) scene. He recovers, though, and tells Piggie that while he might not like her food, he still likes her. Scored cutely by Simon, it is funny, catchy and in the end moving, a paean to friendship and trying new things.“Everything that I do as a picture book writer is reductive,” Willems said, reflecting on what writing his first libretto taught him, aside from the importance of placing consonants carefully. “If you look at a picture book manuscript, and you can understand it, it has too many words. If you look at just the illustrations, and you can understand it, the drawings are too detailed. They both have to be incomprehensible. It’s very similar with writing an opera, that the words that you’re using have to be dependent on the music, but the music has to be dependent on the words, and either of them shouldn’t really be able to stand alone.”WILLEMS CAUGHT THE opera bug and started planning a follow-up, “Don’t Let the Pigeon Sing Up Late!,” which O’Leary said was initially conceived as a monodrama for the inquisitive, intransigent Pigeon — akin to an avian “Erwartung.” Deborah Rutter, the Kennedy Center’s president, also suggested that Willems collaborate with Fleming, the center’s artistic adviser at large.Fleming sent Willems reams of classic arias to listen to, select from and rewrite to fit how kids might experience emotions like joy, disgust or shame. “They are sung beautifully,” Fleming said of the results. “They are sung in all seriousness. It’s just the text. A, it’s in English, and B, it’s really devised for 6-year-olds.”Curry, center, preparing the premiere of “Don’t Let the Pigeon Sing Up Late!”Lexey Swall for The New York TimesSimon, right, the composer of “Don’t Let the Pigeon Sing Up Late!”Lexey Swall for The New York TimesSmushed together under the title “The Ice Cream Truck Is Broken!” so that nine rewritten arias surrounded the Pigeon opera, the hourlong show ended up being a bit of a mishmash, as if the remarkable sum of resources being drawn from all over the Kennedy Center — not least, its comedy budget — were being thrown around to see what stuck.The arias didn’t quite land, to judge by the polite but not thrilled reactions of the children sitting near me. Dressed to the nines, Willems and Fleming introduced them, laboring over a running joke about an “opera song” really being called an “aria.” Felicia Curry, a leading Washington actress, directed with a light touch, sharing with her collaborators a faith in the music itself to connect. Though the early-career singers — Suzannah Waddington, Siphokazi Molteno, Oznur Tuluoglu, Jonathan Pierce Rhodes, Shea Owens — were amplified and could not possibly have sung more clearly or enthusiastically, it was still hard for my young assistant either to follow the lyrics with her ears, or to sound out the supertitles in time. I found some of the texts ingenious, but it all felt a bit too earnest, too consciously instructional to inspire.She was there, in any case, to see a bird sing; and sing the Pigeon did. After eight of the arias and a fair bit of fidgeting came the Willems-Simon piece, which is based on “Don’t Let the Pigeon Stay Up Late!,” a past-bedtime classic in which the Pigeon works through a repertoire of tactics to ward off sleepy time. Tuluoglu, a young soprano whose most recent prior role was Barbarina at the Annapolis Opera, took on the title character. “When you train, you have to be able to sing Mozart, you gotta be able to be a pigeon,” she said before the show.Willems adds two cousins to the Pigeon’s flock, and in turn the pajama-clad birds try out a trio of techniques — “Negotiation,” “Guilt” and “Tantrum,” as their arias are called — on an audience that is encouraged to yell back in denial. Simon’s score is a delight, propulsive and charming with a swishing jazz number and a lullaby ripped from Brahms. The kids enjoyed it, and so did the adults.Now, Willems hopes to write the libretto of a full-scale opera.Lexey Swall for The New York TimesTHE HOLY GRAIL of so-called family or education programming must surely be something along those lines, but in the experience of this frustrated musical parent, the recipe is often wrong. Willems and his collaborators understand the same thing as their goal, although as the author said, “no one is a true expert in children’s, Al Yankovic-ing, spoofing opera pieces.” Experimentation is required.“You have to approach it with all the same seriousness” as a main-stage opera, O’Leary said, “and get all the greatest people involved, because actually kids are the toughest audience, the most discerning, and if you can make it work, then you know you’ve got something.”Willems has long written books that transcend generational divides: my children love them because they are silly, and I love them because they make me a sillier father than I would ever be without one in my hand. As a librettist — a description that must now be added to all his other job titles, as he enjoys the collaborative nature of opera so much that he hopes to write a full-scale piece — he inevitably thinks along the same lines. His arias, he said, were for me and my children alike.“She already thinks it’s cool because it’s great music,” Willems said, nodding to my daughter. “You have a history to it, and by stripping that history away hopefully you’ll listen to it differently. You’re coming into it with preconceived notions, and these guys aren’t, and then there’s somebody in the middle who just, like, saw a lot of Chuck Jones films, and has a vague sense of it.”“I struggle,” he added, “with the idea that a grown-up would bring one of the younger people in their lives, with the expectation that that person is going to learn something, but that the person bringing them isn’t. I want everybody to be open to a new experience.” More