After performing 11 songs, Followill said he was going backstage to get a cold beer, and would come back - but he never did.
In a video posted online by a fan, Followill is heard saying: 'My voice is completely 100 percent wrong. I'm sorry… Do you know what? I'm going to drink some beer and I am going to drink some tequila and I'm going to have a good time and for the record I'm not drunk…I'm just f****** hot.'
Followill, who married model Lily Aldridge in May, added: 'I'm about to fall down here because I'm so goddam hot. I have no goddam idea what the f*** is going on, all I know is that I'm married to the prettiest f****** girl in the whole world. I'm gonna go backstage for a second. I'm gonna vomit, I'm gonna drink a beer and I’m gonna come back out here and I'm gonna play three more songs.'
It was later announced that the singer was suffering from exhaustion and dehydration. But Followill's brother and bandmate, Jared, hinted at other issues.
He tweeted: 'Dallas, I cannot begin to tell you how sorry I am. There are internal sicknesses & problems that have needed to be addressed. No words. I love our fans so much. I know you guys aren't stupid. I can’t lie. There are problems in our band bigger than not drinking enough Gatorade.'