Sinead O'Connor's apologised to fans after cancelling her summer tour.
The singer was due to headline a gig at the Galway International Arts Festival tomorrow.
But Sinead's agent says she's suffering from exhaustion due to an existing illness - and her doctor's ordered a complete rest.
American singer John Grant will still play tomorrow's gig and the Sharon Shannon Big Band has been added to the bill.
The promoters are sweetening the pill with a free drink for ticket holders.
Refunds are also available.
