Alex Iwobi has joined Everton from Arsenal for a fee that could rise to £34m.
Iwobi has signed a five-year deal at Goodison Park having come through the ranks with the Gunners, for whom he scored 15 goals in 149 games.
The Nigerian forward is the Toffee's seventh summer signing joining goalkeeper Jonas Lossl, defender Djibril Sidibe, midfielders Andre Gomes, Fabian Delph and Jean-Philippe Gbamin, and striker Moise Kean on Merseyside.
"Alex was one of our main targets for this window and I believe he is a fantastic signing. He is a direct and skilful winger and attacking midfielder who always works very hard," said Everton manager Marco Silva.
"He is still young but already with a lot of top-level experience - 100 Premier League matches, more in Europe and many international games.
"Alex fits exactly the profile of player I want. He is hungry to join Everton and take the next step in his career, to help us compete with the strongest teams in the league and reach his potential at our club."
Iwobi's arrival was announced more than four hours after the window closed after Everton had an initial bid of £30m turned down.