Newcastle have completed the signing of midfielder Mikel Merino on a permanent basis for an undisclosed fee.
The 21-year-old Spaniard joined the club in the summer on loan from Borussia Dortmund but has now signed a five-year-deal at St James' Park.
Manager Rafael Benitez said: "He has made a great impression at the club. He has confidence, but he is still young and has things to improve."
Merino has played in all of Newcastle's Premier League games this season.
Find all the latest football transfers on our dedicated page.