Charli xcx made a surprise guest appearance with The Strokes during the band's headline set at San Francisco's Outside Lands festival, joining frontman Julian Casablancas to sing "Take It Or Leave It" from their 2001 debut album Is This It. The moment highlighted a friendly rivalry between the two acts, whose latest albums were released on the same day, and underscored Charli's growing festival presence following the release of her new record.

Casablancas introduced Charli as "a superstar" and jokingly referenced the chart battle between her album Music, Fashion, Film and The Strokes' Reality Awaits, both released on 24 July; hers debuted at number three on the Billboard 200 against the Strokes' number 13. It was Charli's second guest slot of the weekend, having earlier appeared in a pre-recorded voicemail cameo during Djo's performance of "Charlie's Garden", and her second festival headline show since her album's release, following her Lollapalooza debut on 31 July.