The Strokes star Julian Casablancas stunned fans at Arcade Fire's gig in Argentina on Tuesday night (01Apr14) by donning one of the band's trademark masks and taking the place of the frontman Win Butler.
The rockers kicked off their set at the South American branch of the Lollapalooza festival in Buenos Aires wearing their huge bobble head props.
As they began playing their song Rebellion (Lies), the crowd gasped when Butler stormed onto the stage and tackled the 'frontman', pulling off the mask to reveal the imposter as Casablancas.
The audience went wild as Butler played up to the joke, which came on April Fool's Day, with the rocker shouting, "What the f**k is this? Get out of here. Not cool."
He then took his place in front of the microphone.
Casablancas is also performing on Lollapalooza's Latin tour, which hit Chile last week (beg24Mar14) and will travel to Brazil over the weekend (05-06Apr14).