Chelsea have agreed personal terms with Ajax winger Hakim Ziyech over a five-year-deal.
The Morocco international will move to Stamford Bridge for 40m euros (£33.3m) in the summer.
The clubs reached an agreement for 26-year-old Ziyech, who will remain at the Eredivisie leaders for the rest of the season, earlier this month.
“I am proud to have signed for such a huge club as Chelsea,” said Ziyech.
“I am looking forward to next season and hope we can achieve great things.”
Ziyech has scored nine goals in all competitions for Ajax this season, contributing to three goals as the Dutch side drew 4-4 against Chelsea in the Champions League in November.