Heavy overnight rain flooded Chicago's Grant Park and continued into Saturday, forcing organisers to delay the third day of Lollapalooza 2026 by about three hours for clean-up, with some sets cancelled or shortened as a result. Despite the disruption, headliner Olivia Dean and rising British singer Sienna Spiro both delivered standout performances, capping a breakthrough year that has seen Dean go from a smaller daytime stage in 2024 to topping the bill in front of a huge crowd.

Dean's headline set featured songs from her debut album Messy and her 2025 follow-up The Art of Loving, and included a surprise appearance from Sam Fender to perform their duet "Rein Me In." The pair recently set a new UK chart record when the track became the longest-running Number One single in UK singles chart history, spending 19 weeks at the top and surpassing Frankie Laine's 71-year-old record. Earlier in the day, 20-year-old Sienna Spiro drew an enthusiastic crowd to the Airbnb stage with orchestral, horn-driven performances of tracks from her debut album Visitor, including "Pure" and closer "Die on This Hill."