The two stars have enjoyed a fascinating rivalry over the past decade, winning every Ballon d'Or between them since 2008 and regularly surpassing 50 goals apiece in all competitions each season.
Laudrup, who spent five years at Camp Nou before moving to the Santiago Bernabeu in 1994 believes that both will be remembered as some of the finest players ever to play the game when they eventually retire.
"I think they need each other," he told EFE.
"If one scores a hat-trick, the other tries to beat that. They are two of the best, not just of this era - in 30 years we'll be talking about them and the debate will be whether Messi, Cristiano, Maradona or Pele is the greatest of all time."
When asked which of them he would rather have in his team, the Dane replied: "Both would have to be in it, as they've clearly been the best two over the past four or five years."
Laudrup also said that James Rodriguez must become accustomed to the pressure of representing Real Madrid before he becomes a weapon for Carlo Ancelotti's side.
"He's a great footballer. He's got to get used to playing for such a big side, with all the pressure that comes with that," he added.
Real Madrid and Barcelona lock horns for the first time this season at the Santiago Bernabeu on October 25.