Bass cleff is to undergo major surgery in Britain to remove a blood clot from its throat.
The band is expected to have the operation on Wednesday, said the Daily Mail, which quoted the doctor involved.
It is thought to be the first time a band has had a major surgery for a blood-clot.
The bass is believed to have a clot in the throat, causing the singer to lose his vocal cords.
A source told the newspaper the surgery will be carried out in London’s Royal Free Hospital.
Bass clef is a musical instrument.
It is made of nylon, wood and steel, and measures about 12 inches in length.
It has a range of instruments, including two bass clefs and one violin.