A deal has been reached to sign Gakpo from PSV.
The club says it is a record transfer fee for them.
At the start of the January transfer window, Gakpo will join the club and his contract will last until the summer of 2028.
Gakpo is looking forward to starting training and playing for the club.
The club is a great place for me to come in and show what I can do and help the team achieve more beautiful moments.
There's a lot of great players here, who I can learn a lot from.
The transfer of Gakpo is subject to a work permit after he scored three goals in the World Cup.
Luis Diaz and Diogo Jota are facing lengthy spells on the sidelines as a result of Gakpo's addition to the squad.
Manchester United had been heavily linked with a move for Gakpo.
He has scored nine goals and provided 12 assists for PSV this season.
He has three goals and two assists in the European competition.
He scored in his country's three games at the World Cup.