Liam Gallagher has apologised to fans after walking off stage mid-concert without explanation.
The former Oasis frontman left the stage at Thursday's Lollapalooza festival in Chicago after just three songs.
Fans were left wondering if the Gallagher brother would return - and had to wait an hour for an explanation which came via Twitter.
"Sorry to the people who turned up for the gig in Chicago lollapalooza had a difficult gig last night which f***** my voice.
"I'm gutted LG x."
Gallagher opened with two songs written by his estranged brother Noel, including Rock n Roll Star, but played just 20 minutes of his hour-long slot.
The annual music festival was later cancelled entirely for the day as thunderstorms loomed.
Lorde and Muse were also forced to pull their performances and festivalgoers evacuated from the premises.
Lorde tweeted after her set was called off that she had "the most spectacular show planned", while Muse's Matt Bellamy wrote on Twitter he was "gutted" for being forced off stage by organisers, calling the experience a "nightmare".
The second day of Lollapalooza is expected to go ahead as scheduled on Friday, with the line-up including Blink-182, The Killers and DJ Snake.