Texas guitarist Alistair McErlaine has been taken to hospital after suffering a brain haemorrhage.
The star is said to be in a “critical” condition and singer Sharleen Spiteri said the band are all “in shock”.
“I am thinking of Ally and all of his family at this time. My thoughts are with them,” she added.
“Like everyone else, I am desperately hoping Ally will get well and pull through. It is a shock. He is a personal friend and all of us are wishing him well with all our hearts.”
McErlaine was taken to a hospital in London on Tuesday (September 8), reports The Daily Record.
A spokesman for the band said: “It is something we are still coming to terms with. Ally is a great lad and well liked by everyone. He has had a bad one.
“We are just hoping and praying that he can come back from this. Our thoughts are with his family. We have been told the next 48 hours are critical.”
“It is a frightening illness,” he said. “I hope he will be OK.”