Chelsea have signed 19-year-old midfielder Mario Pasalic from Croatian club Hajduk Split for an undisclosed fee.
Pasalic was in Croatia's provisional World Cup squad and has represented his country at under-21 level.
The German-born midfielder scored 11 goals in 36 appearances for Hajduk in what was his first full season at senior level last year.
"This is now a new start in my career," Pasalic told the Chelsea website.
"I am a central midfielder, my favourite player is Frank Lampard, and so I am very happy to be a Chelsea player."