Beckham and Ferguson's most public falling-out came in February 2003, when, after a defeat by Arsenal, Ferguson kicked a boot at Beckham that left him with a cut above the eye.
Beckham described it as a "freak accident", adding: "He could never do it again, because I have seen him in training."
But it was Ferguson who provided Beckham with much-needed reassurance following his sending-off during England's World Cup quarter-final loss to Argentina in 1998.
"The first person to call me after that game was Sir Alex Ferguson," said the former England captain. "He said, 'Son, get back to Manchester, you'll be fine' and that gave me strength to actually get through probably the toughest time I've been through in my life.
"My wife had told me we were expecting our first child, so it should have been a happy time and it wasn't. I look back at it and it was such a difficult time, not just for myself, because I knew once I was back in Manchester, I was protected.
"I had the support of the fans. Every single time I walked up to take a corner, the whole stadium stood up and clapped, and sang my name - I get emotional talking about it.
"But it was more difficult for my grandparents. They were being door-stepped by journalists, who were saying things I don't want my grandparents hearing about their grandson.
"The only thing I could do to protect my family was to say 'don't open the door to these people'."
