The Florence + the Machine singer celebrated her 24th birthday at Britain's Reading festival in 2009, and admits it ended in ''carnage.''
She told NME magazine: ''I woke up and did a smaller set in one of the tents, like a surprise gig, and the whole crowd that was there sang me happy birthday.
''We had my birthday party and performed a full set that night, and it ended up in total carnage.
''There was a bar on the stage, and I ended up trying to crowd surf but fell off. I cut my thumb open and there was blood everywhere.
''Half of us ended up in the Accident and Emergency room at hospital. It was basically everything you want from a birthday - lots of blood and crowd surfing.''
Florence will return to the festival to perform on the Main Stage this year, and is excited about bringing a full stage show for second record 'Ceremonials' to the festival.
She added: ''I haven't quite filtered the fact that I'll be performing on the Main Stage. We want to try and bring the visual aspects of this album to the big stage and just try to make the sound as huge as possible.''
The UK's Reading and Leeds festivals will be headlined by Foo Fighters, The Cure and Kasabian and takes place between August 24 and 26.