Ilkay Gundogan has revealed how Liverpool boss Jurgen Klopp used to allow his players to drink while he was in charge of Borussia Dortmund.
Klopp lead Dortmund to back to back titles in 2011 and 2012.
Speaking in Klopp's new biography 'Bring the Noise', the Manchester City midfielder
"We went out quite often as a team," said Gundogan.
"There were a lot of singles in the squad. Sometimes you could see the after-effects in training on Sunday morning."
Gundogan recalls a time when Klopp had to warn his players for partying till 3am after a victory over Bayern Munich.
He said: "Somebody told me a few of you went out during the week… I don't know who, I don't want to know.
"But I can tell you: these players should be happy we won yesterday.
"Otherwise we would have seen the biggest punishment in the history of club football!"