Porto have paid €13.5million to acquire 40 per cent of the sporting rights to their Brazilian forward Hulk and extended his contract until 2016, the club announced today.
"FC Porto inform that they have extended the player's contract until 30 June 2016, maintaining his departure clause at €100million," said the club in a statement to the Portuguese stock exchange.
Hulk, whose full name is Givanildo Vieira de Souza, is the top scorer in the Portuguese championship this season with 23 goals.
The payment to the Uruguyan club Atletico Rentistas means that Porto now own 85 per cent of Hulk's sporting rights.
Hulk, 24, joined Porto in 2008 after the side from northern Portugal paid €5.5million for 45 per cent of his rights.
His total €19million transfer fee means Hulk "becomes the most expensive player in the history of Portuguese football," according to today's edition of the A Bola sport daily.
Porto have already secured victory in the Portuguese title race and lead the table by 19 points from their Lisbon rivals Benfica.
They meet Maritimo this afternoon in their final match of a season in which they are yet to taste defeat in the league.
Andre Villas Boas's side have also reached the final of the Portuguese Cup and the UEFA Europa League.