Chelsea and Atletico Madrid have confirmed they have reached an agreement over the transfer of Diego Costa, subject to agreement over personal terms and a medical.
Atletico will be unable to register Costa until January but the agreement between the two clubs effectively brings an end to one of the most tempestuous transfer sagas of the summer.
The deal is expected to be worth an initial £48.4million with up to £8.8m in possible add-ons included in the deal.
In a statement on their club website the Spanish side confirmed: "Atlético de Madrid and Chelsea have reached an initial agreement for the transfer of Diego Costa. The agreement is pending the formalization of the contract between our club and the Spanish international forward.
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"The English club has authorised Diego Costa to travel to Madrid in the coming days to undergo medical tests and settle his contract with our club."
Costa has been AWOL at Chelsea since the start of pre-season in mid-July and has refused to return to training.
Despite interest from a host of other clubs Costa, who had been told by Chelsea manager Antonio Conte he would not be needed this season, has always had his heart set on a return to Atletico, with whom he won the Spanish league in 2014.
Chelsea are due to face Atletico in Madrid next Wednesday and will be relieved to have reached an agreement ahead of that clash, though Costa will doubtless loom large over the clash.
Costa will depart Stamford Bridge with 59 goals to his name, two Premier League titles and a litany of controversies. Relations with Conte became particularly strained in January when his head was turned by an £80m offer from Chinese Super League side Tianjin Quanjian.
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Negotiations with Atletico were complicated by the transfer ban Fifa imposed on the Spanish side but with all three parties eager to send Costa back to Madrid it appeared inevitable that the 28-year-old would return to Los Rojiblancos for the second time, after spells between 2007 and 2009 and 2010 to 2014.