The boyband star was photographed by Florence's manager, Mairead Nash, with Radio 1 DJ Nick Grimshaw backstage at the festival.
As well as Florence, day two of Reading Festival also brought performances from Odd Future, The Vaccines, The Cribs, Mystery Jets and a headline slot from Kasabian.
The third and final day of Reading Festival gets underway today with performances from Kaiser Chiefs, Bullet For My Valentine, Justice and a Foo Fighters headline slot.
Dave Grohl and co will close the mainstage on Richfield Avenue tonight as headliners, with a set of their greatest hits due to confirm their status as one of the best live bands around.
Kaiser Chiefs and Bullet For My Valentine also play the mainstage today, as well as blues rock duo The Black Keys, who make their final UK appearance this summer.
French disco kings Justice, meanwhile, headline the NME/Radio 1 Stage tonight, following a day's performances from the likes of The Horrors, Two Door Cinema Club and Django Django.
Photos: Kasabian headline Reading eight years after debut