US rock band REM hope to resume their UK tour on Wednesday after bass player Mike Mills was taken to hospital with a severe ear infection.
REM say they will resume touring when guitarist Mike Mills is well
Frontman Michael Stipe said Mills should be well enough to resume the band's UK tour at the Birmingham NEC.
REM were forced to cut short Monday night's show in Sheffield, and cancelled Tuesday's Glasgow date.
Stipe said Mills could "barely stand" let alone play before Monday's concert in Sheffield.
Instead, the rest of the band played a short acoustic set on Monday. The rescheduled show will take place on 15 June.
Promoters are trying to reschedule the Glasgow date.
Stipe said on Tuesday: "Mike is doing better today and we're hoping he will feel well enough to do the Birmingham show tomorrow."
"While we were in Europe he caught flu which has left a lot of people over there hospitalised," he added.
"He thought he was getting over it and managed to do a couple of shows but then it seems to have turned into an inner ear infection and he was so ill last night he was unable to stand.
The band's Tuesday night show in Glasgow has been cancelled
"We're all incredibly disappointed because we're not a band that cancels shows left and right. Last time we cancelled a show for any reason was nine years ago."
Stipe and guitarist Peter Buck went on stage to play four acoustic songs for the 12,000-strong audience in Sheffield.
The pair performed The One I Love, Leaving New York, I've Been High and Losing My Religion.
Stipe said: "We performed without any amps or musicians and Peter and I felt like we were jumping off a cliff. "It was really an apology to the fans, who had gone to great lengths to be there."
The band's spokesman said they would review their remaining dates on a "day-to-day basis", based on doctors' advice to Mills.
"Obviously we all want Mike to get better, and clearly we all want to play the shows. Rest assured we will do so as soon as possible," he said.
The band had originally been scheduled to play four dates in the UK as part of a world tour.
In 1995 former drummer Bill Berry collapsed in Switzerland while the band was on tour, having suffered a ruptured aneurysm.
He made a full recovery, only to leave the band two years later.