The Spain international striker has long wanted a chance to play in the Premier League and is excited to represent "one of the world's greatest clubs."
Jose Mourinho's Chelsea has reportedly agreed to meet the center forward's release clause — in a deal that, including agents' fees, will cost the club 35 million pounds — and struck personal terms that will make him one of its best-paid players.
"It is a thing that is about to happen," Costa told Goal. "Things are going in a direction and, if they keep going as they are going, it is the team I will play for in the next season. I've wanted to play in the Premier League for a while. Chelsea are one of the greatest clubs of the world so there are many factors that make you take a decision like this."
PHOTOS: Opening ceremony | Brazil protests | Soccer fanatics | Fan tattoos
Part of the Brazilian's attraction for the Blues boss is his physically domineering and unconventional style — partially a product of spending his teenage years outside of the country's academy systems. He first represented a top-tier European side as an 18-year-old, having been signed by Sporting Braga's then-technical director Eladio Parames, a close friend of Mourinho.
He subsequently bounced around Portuguse and Spanish club soccer, joining Penafiel, Celta Vigo, Albacete, Valladolid, Rayo Vallecano and Atletico Madrid on either full transfers or loans. Only in his past two seasons in the Spanish capital did he reach double figures in goals scored, concluding with a spectacular haul of 36 from 52 appearances as Atleti won the title.
The 25-year-old is cautious about affirming expectations that his playing style is ideally suited to English soccer.
"Every year is a different story, nothing is easy in life," he says. "I will have to work a lot to fit in with the style of the Premier League."
The striker was roundly booed by Brazilian spectators as he made his World Cup debut for Spain in Salvador, a city less than 300 kilometers from his birthplace, on Friday. He won Spain's penalty in the 5-1 defeat and declared himself unaffected by verbal abuse querying his sexuality.
"In Spain it happens to me in every stadium I play so I'm pretty much accustomed to it," Costa said. "I had my right of choice so it's the same for the public, they have the right to choose to boo me. When you are on the pitch you don't think about those things. I saw it coming, I knew it was going to happen so I had my head ready for that."
The forward also countered suggestions that his Spanish teammates had been affected by the continual name-calling. "From [last year's] Confederations Cup, they knew that here in Brazil the relationhip between Spain and the fans was a bit complicated," he said. "They knew they wouldn't have the support of the public.
"It was a tough loss [but] a match like this happens now and then. There is a positive side which is that we still have a chance, so we have to keep our heads up because there are two finals to be played. There is nothing better than a next match to try to forget this one."