Former Arsenal and Leeds midfielder David Rocastle is battling against cancer.
The 33-year-old has been diagnosed as suffering from non-Hodgkin's lymphoma, which attacks the immune system.
Rocastle has been undergoing a course of chemotherapy for several weeks.
His agent, Jerome Anderson, said: "I can confirm that, unfortunately, David is suffering from non-Hodgkin's lymphoma.
"He has a very young family and, obviously, this is a very difficult time for them.
"Of course, everybody is rooting for him. David is known worldwide and has been a hero to many people throughout his career."
Rocastle made his name at Arsenal where he won the League Championship in 1989 and 1991 as well as picking up a Milk Cup winners' medal in 1987.
He was capped 14 times by England and also enjoyed spells at Leeds and Chelsea, but could not recapture his form and found himself loaned out to Norwich before ending his career at Hull in 1997.