Chelsea and Valencia confirmed on Sunday night that they have reached "an agreement in principle" for Juan Mata to join the west London club.
Neither club has disclosed the fee for the 23-year-old but both confirmed the transfer was subject to the player passing the relevant medical tests.
Chelsea's statement tonight read: "An agreement has been reached with Valencia CF for the transfer to Chelsea of midfielder Juan Manuel Mata. The move is now subject to the player passing a medical and agreeing personal terms."
Valencia's statement was almost identical in wording.
New Chelsea boss Andre Villas-Boas has identified a lack of creativity in midfield as one area which requires improvement before the transfer window closes and will no doubt hope the Spain international can provide some nous to an ageing squad.
Chelsea are not the only English club reported to have shown an interest in Mata with north London rivals Arsenal and Spurs linked with a player who has flourished at the Mestalla after failing to make the breakthrough at Real Madrid.
Mata joined Valencia from Madrid in 2007 and has emerged as one of their most important players, his form earning him a regular place in the Spain squad.
He was a part of the party which won the 2010 World Cup in South Africa and was also a key man this summer as Spain won the Under-21 European Championship in Denmark.