Jimmy Greaves, the World Cup-winning former England striker, was taken into intensive care after suffering a severe stroke on Sunday.
A statement from the 75-year-old's family read: "Football legend Jimmy Greaves suffered a severe stroke on Sunday May 3, and is in intensive care in hospital.
"His wife, Irene, and four children have asked for privacy during what is a worrying time for the family. They will issue a bulletin on his condition when it is appropriate.
"England’s greatest ever goal scorer was 75 on February 20, and has been working regularly on the personal appearances circuit in harness with his friend and agent Terry Baker.
"Jimmy had a minor stroke in 2012, but appeared to have made a full recovery.
"He was due to be inducted into the Tottenham Hotspur Hall of Fame on May 13 at a sell-out ceremony at White Hart Lane.
"This is all we wish to say at the present time."
The former Tottenhamd and Chelsea striker is fourth on England's all-time scoring list with 44 goals in 57 appearances and was awarded his 1966 World Cup medal belatedly in 2009.
Having missed the final due to injury, FIFA eventually ruled that non-playing members such as Greaves - who featured in the first three matches of the competition - should be given replica medals.
At club level, Greaves won the Serie A title with Milan, while twice lifting the FA Cup with Spurs, with whom he also claimed a European Cup Winners Cup crown.
