Billie Eilish is working it out on the remix.

Brat summer continues on as the pop star joins Charli XCX on a new version of her deluxe track "Guess." Charli made the announcement in an Instagram video shared Thursday. The remix drops Aug. 1 at 6 p.m. ET.

Charli asks in the video, "Hey Billie, you there?" before a pounding electric beat comes in.

At the end of the short clip, Charli and Billie are seen falling back into a pile of bras. It's a reference to a lyric from the song, which goes, "You wanna guess the color of my underwear?"

"Guess featuring Billie Eilish - Out at 6pm est," Charli's caption reads.

Billie also posted about the collaboration on Instagram. “‘Guess’ FEATURING ME,” Billie captioned the same clip Charli shared. “OUT 3PM PT TODAY @charli_xcx.”

Copyright © 2024, ABC Audio. All rights reserved.