Chelsea have reached an agreement with Ajax to sign the Dutch club's winger Hakim Ziyech this summer.
The 26-year-old was a January transfer target for Chelsea boss Frank Lampard.
Ajax were unwilling to sell the Morocco international in the transfer window as they chase the Eredevisie title.
Ajax have confirmed they have accepted a fee of 40m euros (£33.3m) - potentially rising to 44m euros (£36.6m) - with the move subject to Ziyech agreeing personal terms.
Speaking on the move, Ajax manager Erik ten Hag said: "I am not surprised by the news about Ziyech. I know that our players are very popular with the big clubs in Europe. That is just great.
"I have known for a long time what Hakim wants. He has a picture in mind. He knows exactly which clubs he finds interesting and which not. Chelsea is a fantastic club. When it is final, I am very happy for Hakim, and I am very proud of it."