Mad Cool Festival 2025 has announced a major shake-up to its lineup, with British rock titans Muse stepping in to replace Kings of Leon as Thursday night’s headliner. The announcement follows news that Kings of Leon have cancelled their entire UK and European tour due to emergency surgery undergone by frontman Caleb Followill.

The band shared their regrets in a statement, explaining that medical professionals advised Caleb to withdraw from live performances to ensure proper recovery. “We’re devastated to miss out on seeing our fans this summer but Caleb’s health has to come first,” they said. The cancellation affects all European dates, including what would have been a headline return to Madrid’s Mad Cool Festival on July 10.

Stepping in are Muse, the genre-defying trio known for their explosive live shows and chart-topping anthems. No strangers to the Mad Cool stage, the British icons bring decades of arena-filling experience and a massive catalogue of hits, promising fans an unforgettable performance to kick off the weekend.

Muse joins a stacked Mad Cool 2025 lineup that includes Olivia Rodrigo, Nine Inch Nails, Noah Kahan, Iggy Pop, Peggy Gou, and Glass Animals. The festival runs 10–13 July at its home in Madrid, Spain.