Johan Cruyff has thanked supporters for their good wishes after it was confirmed he had been diagnosed with lung cancer.
The 68-year-old Netherlands great and three-time Ballon d'Or winner was told of his illness this week after tests.
"Thank you for all your support," said the former Ajax player on Twitter.
Cruyff's son, former Manchester United midfielder Jordi, also said: "Thanks a lot for your supportive messages. Much appreciated."
Cruyff helped his country reach the World Cup final in 1974, where they lost to West Germany.
He also won three consecutive European Cups with Ajax and went on to play and manage at Barcelona, with both clubs sending out messages of support.
Former Ajax, Manchester United, Juventus and Fulham goalkeeper Edwin van der Sar, now a director at the Dutch club, said: "On behalf of the club, I wish Johan and his family a lot of strength and a speedy recovery."
Barcelona president Josep Maria Bartomeu tweeted: "Johan, you'll win this one too. The whole club is behind you."
While in charge at the Spanish club, he led them to their first European Cup win in 1992 and the European Cup Winners' Cup in 1989.
|Ballon d'Or winner in 1971, 1973 and 1974|
|Watch: Cruyff explains how to master his 'turn'|
|Watch: Two goals from Dutch great in highlights of 1974 World Cup|
|Led Barcelona to 1992 European Cup and four consecutive La Liga titles|
They also won four consecutive La Liga titles from 1990-91 to 1993-94.
Widely regarded as one of the greatest players of all time, Cruyff had a double heart bypass surgery in 1991.
Having been a smoker, he gave up immediately after the operation and took to sucking lollipops in the dugout.
He featured in a Catalan health department advert, saying: "Football has given me everything in life, tobacco almost took it all away."
His last managerial appointment came at the Catalonia national team, where he was in charge from 2009 to 2013.