Gnarls Barkley have had to cancel their appearance at next weekend's Electric Picnic festival.

Due to non-stop performances over the last three months, rapper/singer Cee-Lo has put a great strain on his vocal chords and has been advised to cancel his next five shows or risk having more extensive problems.

The promoters of Electric Picnic wish Cee-Lo a speedy recovery.

The duo's hit 'Crazy' was the biggest-selling single of the year, making it into the record books for being the first single to go to number one on downloads alone.

Electric Picnic, Ireland's boutique music festival, takes place over three days, from 1 to 3 September. 

Basement Jaxx, Massive Attack, New Order, Pet Shop Boys, Groove Armada, Antony and the Johnsons and PJ Harvey are among the acts that will perform across seven stages.