Belgian midfielder Maroune Fellaini signed for English Premier League club Everton from UEFA Cup opponents Standard Liege late on Monday for a record 18.5m euros fee.
"Maroune Fellaini has transferred to Everton FC. He has signed a five-year contract," Standard Liege said.
The 20-year-old playmaker becomes Belgium's most expensive player, while the fee paid by Everton is also a record for the English club.
He impressed in his two recent Champions League appearances against Liverpool.
However, Fellaini will not be eligible to play for Everton against his former club in the first round of the UEFA Cup in November, having already played for Liege in the Champions League last month.