Zinedine Zidane has called the record transfer fee paid to bring in Gareth Bale to Real Madrid as "incomprehensible."

Bale completed his world beating €100million (£85.3 million, $133.3) move from Tottenham on transfer deadline day a week ago, and with it smashing the record held by Real Madrid themselves when they paid £80 million ($125 million) to Manchester United in 2009 for Cristiano Ronaldo.

Zidane, who is now Carlo Ancelotti's assistant coach at Real, was pretty vocal about bringing in Bale to the Bernabeu all summer, but finds it hard to fathom the justification behind the transfer fee involved.

The France great was himself a record buy by Real in 2001 and said one would have to wait for a year before deciding if Bale can justify being the world's most expensive player.

"You need to ask that question in a year's time," he told Canal Plus.

"Ten years ago, they bought me for 75million euros and I said I wasn't worth it.

"Today, I tend to say a player is not worth that. Two clubs agree on a price and no-one is forcing the other to do anything.

"That's football. Unfortunately, it's incomprehensible with what's happening today to pay so much."

Zidane believes Bale has the talent and then some to succeed at Real and is more than ready to help out the Welshman whenever necessary.

"My role will certainly be to tell him that he plays as he knows how to, to not put too much pressure on himself," Zidane added.

"He has an incredible potential but he still has room for improvement."

Bale is expected to make his Real Madrid bow on September 14, when the Spanish giants travel to Villarreal. The former Southampton forward's first home game is expected to be on September 22, when Real host Getafe.