Chas Hodges, one half of music duo Chas & Dave, has cancer of the oesophagus.
The 73-year-old will begin treatment “immediately” after the illness was caught “at an early stage”, the band said in a Facebook post.
They added: “Chas recently underwent hospital tests which revealed cancer of the oesophagus.
“Luckily this has been spotted at an early stage and he’ll be undergoing treatment immediately.”
The star “expects to be back out on the road with Dave” soon, but the duo have cancelled several dates scheduled across February.
Performances at Potters Bar, Norwich and in Milton Keynes on February 17, 18 and 19 “will need to be rescheduled”.
“Apologies to ticket-holders for the inconvenience. The venues themselves will advise regarding re-scheduling/refunds,” the statement added.
The duo, famous for hits such as Gertcha and Rabbit, formed in the 1970s and are the creators of a musical style dubbed rockney – a mix of rock and cockney.