Chelsea have completed the 4.35million pound signing of Oriol Romeu from Barcelona on a four-year deal.
The 19-year-old is the second arrival of the Andre Villas-Boas era and will link up with his new team-mates at the end of Spain's Under-20 World Cup campaign.
Barca confirmed Chelsea had paid 5million euros for the midfielder, with the deal including a buy-back clause of 10million euros after one year and 15million euros after two.
The fee was agreed 11 days ago for the midfielder, who was quoted this week as saying: "Chelsea is a great option for me.
"Leaving Barca hurts, but you have to take your chances."
Oriol's agent, Magico Diaz, reportedly jetted out to Columbia this week to seal the deal. That is where Oriol is currently based, having played 90 minutes in Spain's opening two 4-1 and 2-0 victories over Costa Rica and Ecuador respectively at the Under-20 World Cup.
His arrival at Stamford Bridge will help offset the loss of Michael Essien, who faces six months out with a serious knee injury.
Speaking after the fee had been agreed, Villas-Boas said: "It is a part of the squad in which we are struggling with numbers because of Michael Essien's injury and Oriol is a player with a bright future. He still has to evolve as a player.
"The Barcelona B team had a magnificent year in the Spanish second division, they finished third.
"Oriol had an injury during the season but he came back late on and was in time to play for the first team. So he is one of the most promising young players in that position."
Source: PA
