Chelsea have completed the signing of highly-rated midfielder Kevin de Bruyne from Genk, the Belgian club have announced.
The 20-year-old has signed a five-and-a-half-year deal and will remain at the Belgian champions on loan until the end of the season.
De Bruyne, who is predominantly a left-sided player, has been on Chelsea's radar for some time and has played twice against the London club in this year's Champions League group stages.
A statement on Genk's website read: "The transfer of Kevin De Bruyne to Chelsea has been completed. He has signed for five and a half seasons and will continue (playing with) Genk until June.
"His signature was confirmed at 0.30 last night. De Bruyne and his agent will return back today from London, along with general director Dirk Degraen.
"Genk will hold a press conference with (director) Jacob Gunther and Dirk Degraen in which they will clarify the transfer policy.
"Afterwards, Kevin De Bruyne will also give an explanation about his transfer to the English club."
De Bruyne becomes Chelsea's second purchase of the transfer window following the arrival of England centre half Gary Cahill from Bolton earlier this month.
The midfielder joined Genk at 14 and quickly rose through the ranks. He made his international debut for Belgium in 2010 and is seen as one of the brightest young prospects in the country.
He is the third Belgian player signed by manager Andre Villas-Boas following the arrivals of Romelu Lukaku and Thibaut Courtois last summer. Villas-Boas admitted last Friday that De Bruyne was a Blues target even before he took the helm at Stamford Bridge last summer.
"It's a target that's decided by the club, that I knew about for quite some time," he said in a press conference.
"He was under the scrutiny of the club for some time. We've been following this player.
"[Romelu] Lukaku the same, and Petr Cech was the same when we arrived in 2004.
"In the sense that it's the club policy for the future. It's the right thing (to buy him) and I'll do everything in my power for him to reach maximum potential.
"But it's down to the club in decision-making."
Chelsea, who play Swansea tonight at the Liberty Stadium, have also been linked with Shakhtar Donetsk midfielder Willian this month, although Villas-Boas admitted last week that a move for the Brazilian is unlikely ahead of tonight's 11pm deadline.