— Chelsea FC (@chelseafc) July 15, 2014
However, the fee is undisclosed but according to reports – It is understood that the Spaniard has joined the Premier League club for around £32 million.
The 25-year-old, who joined Atletico in 2010 from Real Valladolid, netted 35 goals in 44 games last season, as he led his club to their first La Liga triumph since 1996 and reached the Champions League final.
The Brazil-born forward has delighted to join the Blues, “I am very happy to sign for Chelsea. Everybody knows it is a big club in a very competitive league, and I am very excited to get started in England with a fantastic coach and team-mates. Having played against Chelsea last season I know the high quality of the squad I am joining,” Costa told Chelsea’s official website.
“I would like to thank everybody at Atletico who made me into the player I am, it was an incredible time for me, but now I am starting a new adventure and I hope to win many trophies with Chelsea.”