Sunderland have signed midfielder Jules Ahoka from Belgian side Royal Antwerp for 10m euros (£8.6m).
The Black Cats said the 20-year-old DR Congo youth international has signed a long-term contract with the club.
“I am very happy and proud to join Sunderland,” said Ahoka, who featured in both of Antwerp’s league games this season.
“It is a big club with great ambitions, and I am excited to be here.
“I want to work hard, learn from my team-mates and the staff, and continue developing as a player. I will give everything for the club and I cannot wait to get started.”
Ahoka becomes the Black Cats’ third summer signing, following the arrival of Belgian left-back Thomas Meunier and French right-back Dayann Methalie.
“Jules is a player we have been following closely and he has shown some very encouraging qualities for his age,” said Sunderland director of football Florent Ghisolfi.
“He has huge potential and we believe Sunderland is the right environment for him to continue his development.”
Sunderland were beaten 2-1 by Ipswich in their Premier League opener on Saturday. Their next match is against Fulham on Sunday (14:00 BST).
