Tottenham have confirmed Cardiff and Wales full-back Chris Gunter will join them in the January transfer window.
Gunter was in the stands as Cardiff beat Sheffield United on Saturday
The two clubs have agreed a fee thought to be worth £3m for the 18-year-old made up of an up-front sum with add-ons for appearances and a sell-on clause.
Spurs are short of options on the left with long-term injuries to Benoit Assou-Ekotto and Gareth Bale.
Newport-born Gunter broke into the Bluebirds first team last season and has won three full Wales caps in 2007.
We could have offered him three times the amount Tottenham will offer but he wouldn't have stayed
Cardiff manager Dave Jones
Gunter generally plays at right-back for the Bluebirds, but is also comfortable on the left.
Cardiff have previously suggested that they may have to sell players because of cash-flow problems, with their court case with creditors Langston still pending.
But chairman Peter Ridsdale said the decision to sell Gunter is not directly to help ease the club's financial problems.
"I think with the price itself we would have had to consider it no matter what the situation was financially," he said.
"Clearly given the challenge we've had with Langston, it's made the financial security of the club more acute that we do look at this sort of transfer.
"But if Chris had said he wasn't interested in going, we wouldn't have sold him."
Gunter made nine full league appearances and six as substitute in the 2006-7 season, and in May became Cardiff's youngest Wales international when he faced New Zealand at the age of 17.
He found himself out of the Bluebirds first team this season, but impressed in Wales' draws with the Republic of Ireland and Germany.
That helped the youngster reclaim his club place, and he played a part in the Bluebirds' climb out of the Championship relegation zone.
Boss Dave Jones added: "We could have offered the boy three times the amount that Tottenham are going to offer him but he wouldn't have stayed.
"He has now moved on to a completely different level."