The halls are decked. The season, as you know, is meant for jolliness. And there's no jollier place than Z100's iHeartRadio Jingle Ball 2019, the five-hour mini festival concert marathon that lit up New York City's Madison Square Garden like a Christmas tree on Friday night (December 13).

Every Jingle Ball is special, but as this year's first act Taylor Swift reminded us during her set, this one was particularly notable. It doubled as her 30th birthday party, with over 20,000 well wishers singing to her and a three-tiered cat cake to make her smile. And that was just the beginning.

The Jonas Brothers rocked out in their yuletide finest. Niall Horan's festive red pants were a big hit. Lizzo literally wore a Santa suit to preach a gospel of self-love and acceptance. Whether you grew up on an actual Christmas tree farm or want to celebrate from afar anyway like it's (already) Christmas, everyone had something to love at Jingle Ball. Here are the most sizzling moments that heated up this holiday concert.

Taylor Swift took us all to her "Christmas Tree Farm"

After blasting open the show with "Blank Space" and a sparkly dress, Taylor popped on a Santa hat and dove right into her twee new holiday anthem. But before that, the birthday girl spent "the first show of her 30th year" singing "Welcome to New York" acoustically, commanding a twinkling sea of iPhone lights during "Lover," and laying out exactly how to her, love means equality. "Everyone who disagrees needs to 'Calm Down,'" she winked. And then together, we all collectively shook it off — the driving rain outside, our anxieties, the "toxic male privilege" of the music industry — with one sick beat.

Jonas Brothers, meanwhile, transported us back to New Jersey

Just a stone's throw across the Hudson River from their childhood house in Wyckoff, New Jersey, a packed MSG must've felt like a homecoming for Nick, Joe, and Kevin. To close out their personal record-breaking comeback year (which has conveniently doubled as a menswear showcase), the trio's jacket-heavy Jingle Ball set brought the heat. Flames shot up for classic cut "Burnin' Up." Tempos surged for a pumped-up rendition of "Sucker." Joe's rose jacket really smoked. The brothers likewise donned ceremonial Santa hats for a festive "Like It’s Christmas," because it's the rules, and reflected on how far they've come. "The last Jonas Brothers show on this stage was 12 years ago," Nick said. Back then, they surely weren't such snappy dressers. (Just look at that topcoat!)

We Lauv a good surprise

Though not billed on the official Jingle Ball itinerary, Lauv crashed the show in an excellent jacket of his own — a wintry pale blue one at that — to twirl around and deliver "I'm So Tired." Sadly, his collaborator Troye Sivan was nowhere to be found, but in that moment, Lauv didn't need him. He just kept dancing on his own.

Monsta X literally took their own breath away

Monbebe know: Monsta X can really do the damn thing. After sprinting through a highly stylized and choreographed opening number, the six had to stop for some air before they charged back up for another. They wisely took the opportunity to introduce themselves before diving into "Who Do U Love?," then offered a simple plea: "This song came out five days ago," they said about "Middle of the Night." "Please remember us with it!" From breakneck choreo to slo-mo dance-pop and a grand finale centered simply around their tender voices and their mic stands (and some excellent berets), Monsta X showcased their versatility. But Monbebe already know that.

Fletcher lives out her childhood dream

Like Halsey after her and Nick Jonas before her, Fletcher made sure to shout out her New Jersey roots as she ran through her collection of determined breakup pop tunes like "Undrunk" and "One Too Many." For her, hitting the Jingle Ball stage is a dream come true since she spent so many years in the crowd as a fan. "This is the craziest thing I've ever done!" she said. "I've been in these seats." She also admitted she saw the JoBros years ago from section 225 and even tried to sneak backstage.

Lewis Capaldi Christmas gift to us? An unexpected cover

Niall's best bud and self-described "chubby young man" Capaldi was given a gift of his own: a burly yet nimble voice that can fill arenas with a simple melodic swell. He did just that on "Before You Go," flooding MSG with astounding power. He naturally closed out his brief yet memorable set with "Someone You Loved" and even jokingly called it his one-hit wonder moment. But the real present to us was his aching take on Vanessa Carlton's indelible piano-pop hit "A Thousand Miles," which Capaldi completely made his own. Christmas came exactly 12 days early this year.

No one bested Niall Horan's spirit — or his red pants

Lewis's proper pal hit the stage looking like a White Stripe, zipping right into "On the Loose" and letting his band jam on an extended Fleetwood Mac-type groove before getting deep into sad-bastard ballad territory. He also dropped an F-bomb on "Too Much to Ask" as we crossed into 10 p.m. (FCC safe harbor, baby!) and got MSG rocking with the one-two punch of "Nice to Meet Ya" and "Slow Hands." "Let's tear the roof off this place," he instructed; he also plugged his upcoming SNL music slot. Well played, Niall, but next time you play a gig with Mr. Capaldi — or, say, a whole tour — how about a quick duet? Is that... too much to ask?

Lizzo Claus came to town

Sure, she wore the Kringle cape in L.A., but in New York, Lizzo one-upped herself, donning a full-on Santa suit to give those impressive vocal runs on "Cuz I Love You" added shine. "You gotta listen to Santa Claus," she told the crowd before letting us know MSG on her watch was to be a "shame-free zone." At this point, any Lizzo set is a greatest hits romp, but here, they really played like it: "Good As Hell" and "Tempo" and "Juice" and, to a rapturous reception that made the seats around me begin vibrating, "Truth Hurts." "I've had things happen to me I never dreamed of," she offered midway through her set, reflecting on a massive 12 months. Not a bad cap on 2019 — or as we might refer to it decades from now, the Year of Lizzo.

5 Seconds Of Summer pumped the place back up near midnight

2019 brought a whole new side of 5SOS, darker-edged and influenced by Nine Inch Nails and New Order. They kept it classic to start, of course — "She Looks So Perfect" is an eternal crowd pleaser — but Luke, Michael, Ashton, and Calum ruled the later part of the evening by turning the volume way the hell up. Their silky Charlie Puth collab "Easier" sounded like a stomper, and "Teeth" live is basically a nu-metal song. Though they didn't team up with Monsta X for the ultimate mash-up of songs called "Who Do You (U) Love," the quartet did mirror the K-pop group's color palette — which is to say they wore all black. (No berets though. Next time.)

Halsey lit up the place with a final buzzer beater

The Halsey just hits differently at midnight, you know? Though MSG's curfew cut her dynamic set a bit short, H used every second wisely. She blasted the stage with fire for "Nightmare." She shouted out her Garden State upbringing before and during "Bad at Love." She brought it down for a moment with "Graveyard," only to close out Jingle Ball 2019 by revisiting, as she said, the No. 1 most-played radio song of the year, "Without Me." When she was a kid, she said, she'd pretend to be sick so she could stay home and try to call in for Jingle Ball tickets. Now, she gets to watch the other performers up close. It's the most wonderful time of the year.