Charlotte Aitchison, more famously known as Charli xcx, has been a singular force within pop music since long before she painted the world slime green with her culture-shifting, rave-inspired sixth album, BRAT. With one finger on the mainstream pulse and two feet planted firmly in the underground, Aitchison is that rare talent whose boundary-pushing experimentation is cemented with proven hitmaking prowess. When writing for others, her preternatural musical savvy manifests through endlessly sticky melodies and a snappy hook, as in “I Love It” by Icona Pop and Iggy Azalea’s “Fancy”, both of which she features on. As an artist, she exercises a more experimental approach, embracing the conventions of pure pop—only to cut them with elements of everything from punk rock and UK garage to electroclash and R&B—then dialling them all up past the limits. Dramatic synth-pop tracks like “Good Ones” may not share any obvious similarities with, say, the sugary, 8-bit sparkle of “Boys”; likewise, BRAT highlight “Von dutch” vibrates with irreverent bombast in direct contradiction to the frank vulnerability that coaxed Lorde into opening up on the “Girl, so confusing” remix. The polarities are what binds Aitchison’s discography together, however, signposting the zigzagging course she has charted across a career defined through endless reinvention.