Wayne Rooney and Cristiano Ronaldo visited McDonalds drive-thru the night before a Manchester United game to help with the Portuguese attacker's body.
Juventus star Ronaldo is famous for his physique and is still going strong with Italian champions at the age of 35.
But Rooney, who is now a captain-coach at Championship club Derby County, has revealed that the five-time Ballon d'Or winner wasn't always careful about what food he was putting into his body.
When Rooney arrived at Old Trafford in 2004 - 12 months after Ronaldo joined United from Sporting - he drove the future superstar to matches and training.
However, the two teenagers were forced to make a detour one evening as Ronaldo needed to bulk up his wiry frame.
"With Cristiano, when I first got to United we used to go to games and training together. I remember the night before a game stopping off at McDonald's because he wanted a Big Mac," Rooney said in an interview with the Times.
"He was trying to put weight on because he was so thin. I was driving the car, having to go through the drive-through to get him a Big Mac."
Ronaldo and Rooney formed a deadly duo at the Theatre of Dreams, going on to win the Champions League, Premier League, League Cup and Club World Cup together - with only the FA Cup eluding them.
Rooney continued on at Manchester United for the bulk of his career before moving to the MLS and finally settling at Derby, while Ronaldo joined Real Madrid to win another four Champions League titles and a swag of team and individual honours.
The Portugal international is known to now have six meals and five naps a day as he attempts to prolong his career at the highest level with Juve - a work ethic that Rooney finds incredible.
"With four kids I don't know how he fits that in," Rooney said.
"You've got Ronaldo, who looks a million dollars, whereas I've never had the best body, but I can play 90 minutes, I can train every day. I have no worries physically. When I do, I'll stop."