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.

Prior to Eilish, Christopher Cross won the four awards in 1981. She was also the first woman to accomplish the feat. That isn’t all, though. Eilish’s Album of the Year win made her the ...