Chelsea have agreed a five-year contract with Hakim Ziyech, who will join the club from Ajax in the summer.
A deal to sign Ziyech, 26, was recently agreed with the Dutch outfit.
Blues boss Frank Lampard wanted to sign him during last month’s transfer window but Ajax were determined to keep him until the end of the season.
Negotiations between the two clubs continued and a fee of around £38m was agreed.
The player himself has now agreed personal terms.
“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.
Lampard was keen to add at least one attacking player to his squad during the January window but the club’s approaches for a number of forwards, including Paris St-Germain’s Edinson Cavani, came to nothing.
That led to Olivier Giroud staying at Stamford Bridge despite pre-deadline interest from Inter Milan.
Ziyech is a Morocco international, having previously played for the Netherlands at Under-21 level. He can play on either wing or through the middle.
He began his career with Heerenveen and was signed by Ajax from FC Twente during the summer of 2016.