Ajax have agreed a €40m (£33.6m) deal, potentially rising to €44m, to sell Hakim Ziyech to Chelsea in the summer.
The 26-year-old will complete the transfer on 1 July. Chelsea had hoped to sign the Morocco winger in January but Ajax were unwilling to sell mid-season.
Chelsea said the transfer was “subject to the player agreeing personal terms”.
Ziyech bolsters Frank Lampard’s squad in a position in which they will lose Pedro in the summer. There are also doubts over the future of Willian, whose contract expires in June and who wants more than the one-year extension on offer.
Ziyech has assisted more than 20 goals in each of the last three seasons, including 21 in this campaign.