Former Manchester United boss Sir Alex Ferguson has undergone emergency surgery for a brain haemorrhage and is recovering in hospital.
Sky Sports News reported on Saturday evening that the 76-year-old was in a "serious condition". The club later confirmed Ferguson had had an operation.
He is in intensive care at Salford Royal hospital in Manchester having been taken there after falling ill at home.
A Manchester United spokesperson said "the procedure has gone very well but he needs a period of intensive care to optimise his recovery".
They added that the Ferguson family had requested "privacy in this matter".
Ferguson won 38 trophies, including 13 league titles and two Champions Leagues, over 26 years at United before he stepped down in 2013.
Cristiano Ronaldo, signed by Ferguson as an 18-year-old in 2003 and developed into one of the world's finest players in his six years at Old Trafford, tweeted: "My thoughts and prayers are with you, my dear friend. Be strong, Boss!"
Former Manchester United midfielder David Beckham said on Instagram: "Keep fighting Boss. Sending prayers and love to Cathy and the whole family."
Michael Carrick, set to retire at the end of the season, added on twitter: "Absolutely devastated to hear about Sir Alex being unwell in hospital. All my thoughts and prayers are with him and his family. Be strong Boss."
A Liverpool club statement read: "A great rival but also a great friend who supported this club during its most difficult time, it is hoped that Sir Alex will make a full recovery."
Ferguson was recently seen for the United clash with Arsenal at Old Trafford when he presented departing Arsenal boss Arsene Wenger some end-of-season silverware.
There were concerns on Saturday afternoon when his son Darren Ferguson missed Doncaster's final game of the season against Wigan due to "family reasons".
Ferguson was due to be in the dugout at the Keepmoat Stadium but a Rovers statement read: "Darren asks for privacy, and will provide an update through the club during the week."
Sir Alex began his playing career aged 16 with Queen's Park in 1957 in Scotland. He also played at Rangers from 1967 for two years before retiring in 1974 when with Ayr United.
His management career began at East Stirlingshire at the age of 32 before winning his first trophy with St Mirren in 1977.
Aberdeen was where he really made his mark, securing three Scottish titles, four Scottish FA Cups, one League Cup and the European Cup Winners' Cup in 1983.
He picked up the Scotland reins for the 1986 World Cup in Mexico following Jock Stein's death and joined Manchester United later that year.