The singer has pulled out of the Galway International Arts Festival in her native Ireland on Thursday (23Jul15), in addition to a slew of other gigs.

A statement from event organisers, released on Tuesday (21Jul15), reads: "With regret Galway International Arts Festival... wish to announce that due to illness Sinead O'connor has now cancelled all of her summer dates including her Festival Big Top show scheduled for this coming Thursday 23 July."

O'Connor's agent adds, "Sinead O'connor apologises profusely to her fans but she cannot travel this summer anymore. She is suffering from exhaustion due to an existing not resolved medical situation and she has been advised by the doctor to stop any activity and rest. Because of this she is completely unable to travel and to perform."

John Grant, who was billed as O'Connor's support act, will now headline the Galway show.

The Nothing Compares 2 U singer became a first-time grandmother when her eldest son Jake and his girlfriend Lia welcomed a little boy on Friday (17Jul15).

O'Connor broke the happy news on Facebook.com by posting a cartoon which spelled out the words "It's a Boy".

She alerted fans to the fact her son's girlfriend had gone into labour on Thursday (16Jul15), writing, "OMG! Am literally hours away from the greatest dream of my life coming true! #Granny! (sic)."

And she previously told fans, "Always wanted to be a granny. In fact that's the only reason I had kids (joking)."