Comment on Charli XCX's 'Brat' era is making remixes fun again. Other pop stars should take note.

Billie Eilish and Charli XCX.Terrence O'ConnorCharli XCX released a new version of her fan-favorite song "Guess" on Thursday featuring Billie Eilish.The "Brat" remixes all feel like major events, each adding a new dimension to the original track.This stands in contrast to the standard, predictable attitude toward remixes in pop music.Billie Eilish has gleefully joined the extended "Brat" universe with her featured spot on "Guess," a fan-favorite track from Charli XCX's latest album.The much-anticipated "Guess" remix dropped on Thursday with an accompanying music video, which portrays Charli and Eilish as flirty underwear fiends who, at one point, roll down a mountain of bras and lingerie.The whole thing is fun, cheeky, and deeply entertaining, a vibe the kids online might describe as "unserious."It's the latest in a series of "Brat" remixes that feel like proper stop-what-you're-doing-and-listen events, rather than cash grabs or flagrant bids for higher Billboard peaks.Eilish joins a fascinating cast of characters that includes Addison Rae ("Von Dutch"), Robyn and Yung Lean ("360"), and especially Lorde, whose self-awareness and vulnerability on the "Girl, So Confusing" remix thrilled fans and critics alike, transforming her appeal to "work it out on the remix" into an internet phenomenon overnight.Each remix adds a new dimension to the original track, referencing and expanding the lore that surrounds "Brat" and Charli's entire career: Rae sings that people have "a lot to say" about her debut EP, which included the song "2 Die 4," a collaboration with Charli that helped legitimize Rae's arrival in the music world (or at least, the corners of the world where gay people like to hang out); Charli, Robyn, and Yung Lean all trade quips about their talent and status as "three child stars out here doing damage," sounding like a cult-classic reboot of Timbaland, Justin Timberlake, and Nelly Furtado's "Give It To Me." Most notably, "Girl, So Confusing" was entirely inspired by Charli's competitive history with Lorde, a rich conflict that Lorde defuses with a masterful stroke: "I'm glad I know how you feel, 'cause I ride for you Charli."Now, with "Guess," Eilish enters as both a foil and hopeful love interest.