​Cristiano Ronaldo has described former Manchester United boss Sir Alex Ferguson as his 'football father', revealing the close relationship that the pair shared before the Portugal superstar moved to Real Madrid. 

Speaking in an upcoming documentary on the ​BBC called "Sir Alex Ferguson: Secrets of Success," Ronaldo revealed one particular memory he had of his time playing for the 73-year-old, who recently described him as one of the four truly world-class players he managed in his time at Old Trafford. 

He said: "When my dad was sick in London and was in hospital -- very bad, in a coma -- I had a conversation with [Ferguson]," Ronaldo said. "I said, 'Boss, I don't feel good.' We are in a key moment in the league and the Champions League, but I say, 'Boss, I don't feel good. I want to see my dad.

"[He said] 'Cristiano, you want to go one day, two days, one week, you can go. I'm going to miss you here because you know you are important, but your dad [comes] first.' When he told me that, I thought, 'This guy's unbelievable.'"

He revealed that Ferguson created an almost family atmosphere within the club with the compassionate side to his personality, a long way from his famous 'hairdryer treatment'. Ronaldo said: "He invites everyone to come for lunch, come for tea... an English cup of tea! It was a family with him. He was a football father for me."

The famous Ferguson temper was far from a myth though, with Ronaldo saying: "I remember sometimes when we do something bad or we lost some games he kick the chairs and he kick the boots, he kick everything, the waters, the drinks, and he’s so red and ‘f**k you, you should pass the ball you. It was unbelievable but it was good - because we learn."