Everton have completed the £23.6m signing of Ajax captain Davy Klaassen on a five-year deal.
The Netherlands midfielder, 24, has made 163 appearances, scoring 49 goals, since his debut for Ajax in 2011, winning three Eredivisie titles.
"It is difficult to leave Ajax but I think this is a good step for me now," Klaassen told Everton's website.
Everton earlier signed Jordan Pickford, 23, from Sunderland for £25m - a British record fee for a goalkeeper.
Klaassen joins Pickford as another new signing with manager Ronald Koeman determined to build on last season's seventh place that brought them Europa League football.
The 2016 Dutch footballer of the year skippered the Ajax side that lost to Manchester United in last season's Europa League final.
He became a priority signing for Koeman as doubts persist over the future of fellow midfielder Ross Barkley, 23, who has been told he will be sold if he fails to sign a new contract at Goodison Park.
Klaassen added: "The moment that I spoke with the manager directly I got a good feeling. He is an honest guy, we talked about the club, about the way he wants to play and that gave me a positive feeling."
Koeman said: "He is a player who is only 24 but has a lot of experience and is a leader on the pitch. He has already captained Ajax for two seasons and that shows you the type of person he is.
"He is hardworking, likes to press and, of course, will give us more creativity and goals."
The Toffees have also been strongly linked with a £16m move for AC Milan striker M'Baye Niang. The 22-year-old had a spell on loan in the Premier League at Watford last season.
Director of football Steve Walsh was seen in Milan on Wednesday as he pursues a selection of high-profile Everton transfer targets.
Find all the latest football transfers on our dedicated page.