“Who's gonna get f---ed up tonight?!” screams British firestarter Charli XCX, bounding onto a stage inside The FADER x Masterpass pre-Grammy shindig at the former site of Tower Records in Los Angeles on Saturday (Feb. 11).

Gathered in front of her are rabid raving fans, feeding off Charli's onstage euphoria. Around the room are the likes of Macy Gray, Diplo, Grammy nominee Benny Blanco, Brooke Candy and A-Trak, who'll DJ after Charli.

Onstage behind XCX are British electro-pop masterminds AG Cook and SOPHIE on the decks. Cook is the bespectacled brainchild behind PC Music, the uniquely synthetic pop label/genre that beguiled Charli over a year ago now and has since informed her new musical leanings. The two collaborated on last year's Vroom Vroom EP and on latest single “After The Afterparty,” which teases a forthcoming third LP from XCX due later this year.

SOPHIE, who cuts a Bowie-esque figure in slicked-back hair and dark lipstick, is widely considered one of the hottest new producers in L.A. at the moment and has been associated with AG's PC Music for years. Not only is AG performing onstage with Charli regularly of late (he featured in both her Jimmy Kimmel performances earlier this week), he's also her full-time creative director.

Cook and SOPHIE open the set with a selection of mixes on the decks, as Charli gets pumped up on the sidelines in a two-piece and shiny cap, the latter as bright as the beats about to blast faces off here before a hyperactive audience. Injecting the crowd with a gnarly adrenaline shot of last year's “Vroom Vroom” to begin with, Charli then launches into a series of never-before played forthcoming tracks from a mixtape due to drop very soon, all of them pushing the PC Music sound to its most melodic extremes.

“It's the best mixtape ever,” she says.

New tracks played here include “Dreamer” (think the hard house of Livin' Joy's “Dreamer” from 1994 but far better executed), “No Angel” and “Pull Up.” For “Pull Up” Charli invites guest vocalist Mø onstage to share lyrics and the two jump up and down towards each other gleaming. “No Angel” receives an amped-up intro: “This song is a new song. It's my favorite song ever,” smiles XCX. Also featured are unreleased tracks “Roll With Me” and “Bounce,” which have already had previous live outings. The fans already know every rap on “Bounce.”

While XCX seems to be hitting her stride now, the mutual elation in the room from her fans and peers makes for such an infectious vibe. For the 24-year-old songwriter who started life performing at other people's raves as a teenager, she's finally queen of her own rule-breaking parties. Ending on the recently leaked “Girls Night Out,” the crowd catch on to the lyrics fast, “It's a girls' night out/No boys, no boys!” It's a heady combination of cheek, fun and danger.

Backstage, the joy is palatable, too. “That was the most fun show ever,” says Cook, who confesses the whole setlist was done on the fly, not that you can tell. Diplo and Benny Blanco come by to congratulate Charli on her set before disappearing into the night to prowl around various parties. Charli, too, is gathering her troops for a night on the town. To the faint at heart it might look like she's throwing herself at everything a bit too full-throttle, but Charli XCX is just setting a pace for everyone to follow.

Here's the setlist:

Intro

“Vroom Vroom”

“Dreamer”

“Pull Up”

“Bounce”

“Roll With Me”

(Untitled)

“Trophy”

“No Angel”

“Girls Night Out”