Chelsea have signed Mateo Kovacic on a season-long loan from Real Madrid, with goalkeeper Thibaut Courtois expected to have his permanent move in the opposite direction confirmed later on Thursday.
Midfielder Kovacic, 24, has been at Real for three seasons since joining from Inter Milan.
He helped Croatia reach the final of this summer’s World Cup in Russia.
“I am really happy and excited to be here. It is an amazing feeling,” Kovacic told Chelsea’s website.
“I will try to do my best for this club. It is a new league for me, the beginning is always tough but I am sure the coach and my new team-mates will help me and I am looking forward to a great season.”
Chelsea director Marina Granovskaia added: “He is a perfect fit for us this season, his style is well suited to how Maurizio wants to play and we are sure he will prove to be a valuable asset for the club.”
However, Chelsea have signed Kepa Arrizabalaga from Athletic Bilbao as his replacement for £71m – a world record for a goalkeeper.
The deal for the 23-year-old surpasses Alisson’s £66.8m July move to Liverpool.
He is Spain’s number two behind Manchester United’s David de Gea and has one international cap.