The band had been due to perform at the Summer Sundae Weekender in Leicester on Friday August 14 and were also scheduled to play the Picture House in Edinburgh.
Streets’ mainman Mike Skinner has posted a track entitled ‘He's Behind You, He's Got Swine Flu’, which features Bennett playing bass.
Idlewild will close the main stage tonight, says a statement from a spokesperson for the Summer Sundae Weekender.