Charli XCX on sound of pop music, Jingle Ball performance

"Some days, I'm down for being a pop star. And some days I'm really not," Charli XCX says, failing to clarify what kind of day this has been.

This morning, she was a multi-tasking cyclone fresh off the red-eye from Las Vegas. This afternoon, she was eating peach fro-yo on a private tour of the White House. And now, 90 minutes before showtime, she's backstage at Washington's 9:30 Club, answering questions in a towel and a tiara while her personal makeup artist daubs her features in inky blacks and candy crimsons.

It's war paint, really. When the 22-year-old British pop phenom -- who's on the bill Friday at Z-100's annual Jingle Ball at Madison Square Garden and is the musical guest on "Saturday Night Live" this week -- finally storms the stage in classic cheerleader garb, she's a feral Toni Basil, punching the air, flipping the bird, singing the hits.

It all sounds great. There's a gnarled and vastly superior version of "Fancy," her chart-topping duet with Aussie rapper Iggy Azalea. There's "Boom Clap," that giddy heart-spasm from the soundtrack of "The Fault In Our Stars." There's the fizzy melancholy of "Stay Away" and the bratty vroom-vroom of Icona Pop's "I Love It," which Charli co-wrote.

The best of the rest comes from her sophomore album "Sucker" (out Dec. 16), a sweet-and-sour slalom between new wave and punk.

"I want there to be different dimensions to the music I make -- different sides, and contrasts, and things that might conflict against each other," Charli explains backstage before the gig. "Otherwise, I think it becomes boring."

So she's purposefully chameleonic -- in life and in song, singing from the perspective of the scorned lover and the obnoxious party brat with equal conviction. Her sauciest lyrics can be rude, but not enough to keep them off the radio. She has a healthy contempt for the music industry, but not enough to insult anyone signing her checks.

SEE PHOTOSNotable music collaborations

Does she even need those suits in her corner, anyway? Hype will always be slippery stuff, but nowadays, it's generated most efficiently by enthusiastic online fans, not major-label hype-masters. Charli's ascent feels somewhat emblematic of that tectonic, buzz-making shift.

"I don't think record labels have enough power now to create an artist," she says. "Audiences are clever. People see through the . And there's just not that much money to throw at anymore."

Immersed in the music

Charli XCX -- born Charlotte Aitchison in 1992 -- never really got to forge much of a normal life outside of the music biz bubble. She made her first album at the age of 14 on a loan from her parents (it was never released) and quickly scored a record deal.

But her music still brims with the real-lifeness that defines young adulthood. Her songs chronicle the timeless and urgent pursuit of happiness, wealth, attention, revenge, sex, mischief, good times and true love.

In 2011, she made a regal landing in blogland with two heart-mashers of a very specific mood and stripe -- "Nuclear Seasons" and "Stay Away" -- the songs she still holds most dear.

"I'd always felt like I'd never done anything right before," Charli says. "So I remember when I wrote 'Stay Away' with Ariel Rechtshaid, that was the only song I listened to for a month." Before long, she was doing it right all the time. She co-wrote and sang on Icona Pop's riotous, and later ubiquitous, "I Love It." "True Romance," her 2013 major-label debut as Charli XCX, felt as smart as it was catchy. And her career caught yet another wind this summer with the runaway success of "Fancy" and "Boom Clap."

She makes the songs hers

When it came time to hunker down for "Sucker," Charli rented out an abandoned hotel in rural Sweden where old paintings hung on the walls, old chandeliers dangled from the ceiling and an old lake could be admired from the windows. So she invited a klatch of songwriters and producers to come help write some hits: Rechtshaid, Andrew Wyatt of Swedish pop group Miike Snow, Pontus Winnberg of songwriting powerhouse Bloodshy & Avant, Rostam Batmanglij of the rock band Vampire Weekend and some others.

But despite the motley pedigrees of her collaborators, the result always sounds like a Charli XCX song.

"She can capture lightning in a bottle, so to speak," says Batmanglij, who co-wrote "Need Your Love," the grand finale and crown jewel on "Sucker." "It sounds kind of obvious, but the reason her songs are hers is because she's such a huge part of writing them. But that's unique for pop."

Charli wishes it wasn't. She doesn't want to feel like an outlier in a too-drab, too-rigid hit factory.

"The thing I hate so much about the music industry right now is that everybody thinks you have to become a brand to sell," she says. "I think that's so weird. I obviously understand it, but I think the best artists are the ones who continue to change and evolve."

While Charli posits herself as a songwriter with complete creative control, she also acknowledges that the worldwide release of "Sucker" has been delayed this autumn while the rest of the planet catches up to the excitement she has generated in the States. She's very much her own pop star, but there are still strings attached.

"There's always going to be a weird mystery-like lie around pop music -- which is also kind of cool," Charli says. "That's why people like it. And that's why musicians are involved in it. Musicians like drama, even when they say they don't. We're all just big attention-seekers working in a little bubble."

WHAT Charli XCX takes part in Z-100's Jingle Ball

WHEN|WHERE 8 p.m. Friday, Madison Square Garden

INFO $51-$351, 800-745- 3000, ticketmaster.com

MORE "Sucker" is due in stores Dec. 16