Liverpool boss Jurgen Klopp says Sir Alex Ferguson is in his prayers after the Manchester United legend underwent emergency surgery following a brain haemorrhage.
United announced on Saturday that Ferguson had undergone a successful operation, but there has been no further update on the 76-year-old's well-being.
And, speaking after Liverpool's 1-0 defeat by Chelsea, Klopp put club rivalries aside to join his managerial counterparts in wishing Ferguson well.
"I met Sir Alex after the first leg against Roma, he was there with Gerard Houllier," Klopp said.
"I had a few words with them. When I heard it on the way to London I couldn't believe it. He was last night and will be 100 per cent in my prayers.
"I'm looking forward to seeing him again."
Usain Bolt, one of Manchester United's most famous fans, has also offered his support to Ferguson.
The Jamaican joined other sporting personalities in wishing Ferguson well, posting an Instagram picture of him alongside the 13-time Premier League winner, along with the caption: "Prayers be Sir Alex".
Tributes and messages of goodwill have poured in from across world football, with clubs including Barcelona, AC Milan, West Ham and fierce rivals Liverpool and Manchester City offering solidarity.
Football stars past and present have also offered encouragement to Ferguson, such as David Beckham, Cristiano Ronaldo, Massimiliano Allegri, Sam Allardyce, Mark Hughes, Wayne Rooney, Michael Carrick and David Silva.
Ferguson nurtured Ronaldo at United and the attacker won the first of his five Ballons d'Or under his tutelage at Old Trafford in 2008, having also claimed his first Champions League title the same year.
Ronaldo wrote on his official Twitter account: "My thoughts and prayers are with you, my dear friend. Be strong, Boss!"
Former United defender Rio Ferdinand tweeted "praying for good health boss!" early on Sunday, alongside a picture of him with Ferguson as they celebrated winning the 2012-13 Premier League title.
Ex-England star Paul Gascoigne also said he was "praying" for Ferguson's recovery, adding "you've won everything in life any player or manager dreams of".
Sir Alex I’m praying u get through this,you’ve won everything in life any player or manager dreams of,I as a friend is stunned even though it took you 6yrs to be my mate again,no player has sent shivers down my spine but u did&robbo I’m praying you pull through mate love GAZZA pic.twitter.com/WTpDKJ1MXd — Paul Gascoigne (@Paul_Gascoigne8) May 6, 2018
Former Bayern Munich and Real Madrid coach Carlo Ancelotti added on Twitter: "Impatiently waiting for positive news. Thinking of you my dear friend."
Manchester City boss Pep Guardiola has also sent his best wishes for the Scot makes a speedy recovery.
"Brian Kidd, who is [at City] now, was with [Ferguson] for a lot of time," Guardiola told Sky Sports prior to City's game with Huddersfield Town on Sunday.
"So a big hug and our thoughts are with his wife Cathy and the Manchester United family.
"I was glad to have dinner with him two weeks ago, and hopefully he can recover as quickly as possible."