The Florence + the MAChine singer stormed the stage at the fabled music event in Somerset, England on Friday night (26Jun15) after being enlisted to replace the Foo Fighters, who cancelled their slot after frontman Dave Grohl broke his leg.
The headline show came eight years after Welch's first performance at the event, and she reveals her debut nearly ended in disaster.
She tells Britain's Daily Mirror newspaper, "I had to be dragged from someone's tent by as friend - this was the year of the apocalyptic mud. The gig was Sunday and I arrived on Thursday. So by the time it came to Sunday I didn't know who I was, let alone where I was or whose tent I was in. A friend dragged me to the stage. I don't know how I made it because by rights I should've been face down in mud somewhere."