While explanations from festival-goers included "Liam being Liam," Gallagher took to Twitter not long after the abbreviated set to apologize, blaming vocal issues for his early departure.
Gallagher is on the festival circuit to promote his upcoming solo album, As You Were, which is set for release Oct. 6. He has embarked on a typically outspoken press tour leading up to the release, revealing in recent interviews that he's never met his 20-year-old daughter and calling brother and Oasis bandmate Noel Gallagher "a crazy celebrity stalker."
Speaking of Noel, before Liam's apology, this Twitter user credited the set being cut short to her friend's snarky sign:
Lollapalooza continues in Chicago's Grant Park through Sunday, with Thursday night's performers including Lorde and Muse.