Cristiano Ronaldo and David Beckham have both played for Real Madrid and Manchester United.

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David Beckham has urged Cristiano Ronaldo to choose Manchester United should he ever elect to leave Real Madrid.

Beckham admitted he would have 'crawled back' to Manchester had he been given the opportunity after his departure in 2003, the year Ronaldo joined the club.

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The 30-year-old Ronaldo, who spent six trophy-laden years at Old Trafford, has been regularly linked with moves away from the Spanish capital, with Chelsea and Paris Saint-Germain - as well as United - touted as possible destinations.

"I'd have crawled back if I could," Beckham is quoted as saying in several national newspapers.

"But then obviously given the chance once I'd left United, to have played for one of the biggest clubs in the world - with Real Madrid, again it was a dream. But I'd never advise any player to not return to Manchester United.

"Cristiano is such a fans' favourite at United, he was so successful, such a hard worker. Everyone you talk to [says] he's not just one of the most talented players in the game, he's a hard worker as well.

"If he decides to leave Real Madrid then for me personally it's back to United. I never had the opportunity to do so - but I'm proud of the teams I played for after United."

On Saturday Beckham will play again at Old Trafford when he captains a Great Britain and Ireland team against a Rest of the World XI in a UNICEF charity match.

United have been criticised for a perceived lack of dynamism in their play, despite the fact that they are only two points off the top of the Premier League table and on course for the last 16 of the Champions League.

Beckham admits he was fortunate to play in a team that had the perfect blend of grit and guile, a mix he believes was central to their success.

He said: "We've always played with a certain style, with a certain passion, and I think when you play for Manchester United and are around the club you realize that.

"Style is important, but you have to play with a certain passion. Not every team is going to be the same. We were spoiled to be part of an era that gave us that chance.

"I think the style of football has changed over the years, even when I was playing. It was starting to change then. You need fast wingers to get to the byline and cross it.

"We had that fortunately, the likes of Ryan Giggs that went past players, and Lee Sharpe and Andrei Kanchelskis and people like that."