Julian Casablancas gatecrashes Arcade Fire's set at Lollapalooza

Arcade Fire played at the Argentina leg of Lollapalooza over the past few days (although some reports are saying the performance took place in Chile), with their set interrupted by a special guest.

Halfway into a song, the Canadian band’s frontman Win Butler stopped proceedings to point out that the person singing under his papier-mache mask wasn’t actually him. Turns out it was The Strokes’ Julian Casablancas, also performing at the fest.

“Not cool man,” Butler responded to the seeming gatecrash. Although, we’re pretty sure they knew something about it before hand…

Watch below at the 1:34 mark: