Chelsea have reached an agreement with OFK Belgrade to sign highly-rated 16-year-old Slobodan Rajkovic.
Rajkovic, 16, is a regular for the Serbia and Montenegro Under-21s
The Belgrade club says the Premiership champions have agreed a £3.5m deal for the centre-half - a world record for a player under 18 years of age.
"OFK and Chelsea have reached an agreement for Rajkovic," said Belgrade general director Vladimir Bulatovic.
"He will stay with us until the end of the 2006-07 season and then he will join Chelsea."
The Blues have beaten Arsenal and AC Milan to sign Rajkovic who is a regular for the Serbia and Montenegro Under-21s.
The youngster spent time at the Gunners' youth camp last summer and has also reportedly attracted interested from Manchester United, Real Madrid, Monaco, Marseille, Inter Milan, Juventus and Barcelona.