Billboard caught the end of Carpenter’s Tiny Desk rehearsal, which wrapped about 20 minutes before the artist filmed her official performance. She’s already in full glam, but still dressed in a Paul McCartney T-shirt and jeans as she practices belting out her arena-made crowd pleasers in the small, sound-dampening office space in between sips of bottled water through a straw, commanding the room as NPR producers mill about adjusting microphones and volume levels. And yes, she’s just as tiny as she purports to be. Even with her own disclaimer in “Taste” — “I leave quite an impression, five feet to be exact” — it’s still surprising to see how small she looks at the center of the NPR solar system as her band, crew members and office staff orbit around her.

With the exception of the string players, Carpenter’s Tiny Desk band is largely made up of the musicians she performs with on tour, her bassist tells Billboard later — so they’re already in sync. The one instrumental curveball she really needs to nail down before showtime, however, is a set of chimes that she’s in charge of playing during “Juno.” At the moment, she’s trying to decide how frequently she should add the embellishment to the live arrangement, asking someone on her team, “Do we think they get annoyed with the chime bit if I do it too many times?”

“Or …,” she adds while giggling, smiling devilishly as if to say, “Maybe that’s exactly why I should do the chimes too many times.”

When everyone’s satisfied, Carpenter disappears behind the scenes with her posse. “Thanks, guys!” she calls out with a regal wave, her blonde hair bouncing behind her.

After a charged-up audience packs into the space, standing on tip-toes and shifting around to try and get a good view, Carpenter breezes in from the hallway outside, now appearing doll-like in a vintage-looking baby-blue nightgown and stockings. As she walks in, the crowd is either too starstruck or uncertain of what to do to make much noise, so there’s an initial awkwardness that Carpenter immediately disarms when she gets the chance.

“Hi! It was so silent when I walked in!” she says once she gets behind her microphone, unofficially giving people permission to laugh and exhale. Thanks to her, the vibe of the room has instantaneously shifted for the better, even as countless phone cameras come up — the only chance people got to take pictures, as mid-show photos and videos were strictly prohibited — and she obligingly poses for them.

Carpenter then gets a brief introduction from producer Ashley Pointer, who gushes that the singer was her top artist of the year as Carpenter smiles humbly. Later, Pointer tells Billboard that she and the artist’s team have mutually been trying to make the Tiny Desk appearance happen for months, but with the star’s busy schedule, this was the first opening that worked for her.

Then, it’s off to the races. “I’m just gonna start singing!” Carpenter chirps before diving into “Taste.”

True to tradition, Carpenter added her own memento to the hoard of trinkets past Tiny Desk performers have left behind on the office’s cluttered bookshelves. Chappell Roan’s red wig is there, hanging off a skeleton head, while Mac Miller’s “Don’t Trip” hat resides next to a bottle of what looks like Heinz relish.

The “Nonsense” singer went above and beyond for her contribution, adding a custom bedazzled martini glass with her signature red lipstick print on it. Just before starting her performance, she gingerly sets it down on the desk — kissy mark facing out, of course — and gestures at it like it’s no big deal as audience members whoop.

Though the sound quality of Tiny Desk is sharp and immaculate on video, being there in person is a much different experience. There are no speakers, so the only thing anyone in the room with her hears is her raw voice unassisted by any amplification or effects. And the set truly is just your average-looking office space — minus the colorful, trinket-ridden desk seen on camera — meaning there’s no special acoustics to help her out, either.

Even so, Carpenter’s vocals are a force to be reckoned with, the star effortlessly singing over the loud volume of a full backing band with a pitch-perfect confidence. If anything, her voice carries a warmer and fuller tone than it does on recordings.

Her presence is also somehow both intensified and more stripped back in these conditions. She scans the crowd as she sings, her icy blue eyes sending shock waves through anyone she makes eye contact with. When it comes to her cheekiest lyrics — “Come ride on me, I mean, camaraderie,” to name one example — she freely joins in on chuckling with audience members as they crack up, making everybody feel like they’re in on the joke.

After getting through the rest of her set, Carpenter closed the show with “Juno” — the entirety of which builds toward the line, “Have you ever tried this one?”

Every night on stage during her Short n’ Sweet Tour, that lyric was the star’s cue to contort herself into a somewhat NSFW position, sparking viral moments that change from show to show. For NPR, Carpenter instead turned around and perfectly brushed the chimes left to right with her derrière as surprised audience members cheered, not missing a beat as she leapt into the fan-favorite song’s final chorus.

What you didn’t see was the amount of practice the hilarious moment took to execute. An hour prior, before cameras were rolling, Carpenter studiously measured out exactly how close she needed to be to the chimes to get the effect just right, grazing up against the instrument with her posterior numerous times to test it out. At one point, she approached it a little too forcefully and accidentally knocked herself into one of the chimes’ outer edges, loudly yelling out into the office space, “F–k, my a–!” and throwing her head back in laughter.

After the final notes of “Juno,” Carpenter’s Tiny Desk is a wrap. It all happens in one take, too; a crew member asks her if there’s anything she’d like to re-do, but she feels solid. “I forgot the chime, like, once,” she says, before joking, “Should we do it all over again?”

As she leaves, the guests in the audience walk away gushing about her talent and charisma, with one NPR staff member proclaiming how similar she is to Dolly Parton. After everyone finally clears out, Carpenter returns to shake hands, say thank yous, take pictures on the set with her band and snap a few Polaroids with her martini glass — not before her makeup artist touches up her lipstick — as everyone packs up.