Genk's Belgium international Kevin De Bruyne has signed a five-and-a-half-year contract with Chelsea.
As anticipated as part of the agreement, De Bruyne, 20, will spend the remainder of the season at Genk before joining up with Chelsea in the summer.
The attacking midfielder underwent a medical with the Blues on Monday after a reported fee in the region of £7 million was agreed between the two clubs.
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 told Chelsea's official website: "It's a little bit of a dream come true. I've worked very hard and am still very young but have already played a lot of games. To come to a team like Chelsea is a dream but now it's a reality and I have to work hard to achieve the level that's necessary."
Meanwhile, Chelsea also confirmed this morning that 18-year-old Austrian youth international Philipp Prosenik has joined AC Milan on a permanent deal.
The midfielder arrived at the Blues from Rapid Vienna in 2009 but did not make a first-team appearance at the London club.