Alt rockers The Maccabees will play on the Razorlight bill on July 9 and indie pop sensations Florence and the Machine will appear on July 10 at Paul Weller's Session, which is being staged in support of the Prince's Rainforests Project in association with EDF Energy.
Florence and the Machine, comprising London-based singer Florence Welsh and her backing band, won the "Critics' Choice" award at this year's BRIT Awards in February and are due to release Lungs, their debut album, in early July.
The Maccabees, formed in London but now based in Brighton, released their second album Wall of Arms in May this year and saw it peak at number 13 in the UK charts. The record followed their 2007 debut Colour It In.
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