Charli xcx's Brat summer is continuing full-steam ahead — and now Billie Eilish is on board. The two artists released their collaborative remix to Charli's song "Guess" on Thursday, Aug. 1, as well as ...

Billie Eilish's latest concert got the Brat treatment. On Tuesday, Dec. 17, Charli xcx made a surprise appearance at the "Birds of a Feather" hitmaker's Los Angeles concert at the Kia Forum. Just one ...