What's Cristiano Ronaldo like during training?
Well, Edwin van der Sar has recalled a brilliant story involving the then-United super star.
The Dutch stopper arrived at Old Trafford from Fulham in 2005, and became teammates with Ronaldo who joined two years prior after impressing for Sporting Lisbon.
Not to mention Wayne Rooney.
And van der sar has revealed how the pair of attackers worked tirelessly in the training ground to improve their overall game.
Though, according to van der sar, the Portuguese took it to another level.
Ronaldo and Rooney during United training. Image: PA
"They both worked incredibly hard on the pitch, but Cristiano took it up a level," the four time Premier League winning keeper told FourFourTwo.
"Off the field, he was also focusing on everything extensively, such as resting up properly and strengthening his body.
van der sar lines up with Ronaldo and Rooney. Image: PA
Ronaldo, known for his set-piece expertise, often trained after hours to hone his skill, and he'd get van der sar to go in net.
"After training sessions he would often work on his free-kicks and then come to me and say: 'Edwin, can you go in goal?'
"I'd say I was old so he would be better off using one of the youth-team keepers, but he would insist I went in goal as he wanted to score past me.
"I would tease him a lot and say things like: 'You won't score against me, Ronnie, you know it. Ask the reserve goalie, that's better for your confidence.'
"He'd get agitated and reply: 'No, no. You've got to go in goal!'
"Cristiano is a really good guy, however, and the common perception of him is not a true reflection of his personality," he added.
Ronaldo and van der sar next to the Champions League trophy. Image: PA
Ronaldo and van der sar would go onto win Premier League titles, and the coveted Champions League in 2008.
Of course, Ronaldo completed a mega transfer to Real Madrid, while van der sar left United for VV Noordwijk before retiring.