Diego Costa posted a farewell message to Chelsea fans on his Instagram.
The Spanish Striker completed his £58 million move to Atletico Madrid on the eve of the Champions League match between the two clubs at the Wanda Metropolitano Stadium.
Atletico agreed a fee with Chelsea last week to re-sign Costa, who has now completed a medical and agreed personal terms to return to the Spanish capital three years after leaving for Stamford Bridge.
“Diego Costa has today agreed terms for his transfer to Atletico Madrid, which will take effect on Jan. 1, 2018,” Chelsea said in a statement on Tuesday.
“We thank Diego for his efforts and wish him well in his future career.”
The controversial Spaniard’s departure from Stamford Bridge signalled the end of a messy transfer saga.
Costa had a long battle with Blues club after being told he was not in Antonio Conte’s plans for the 2017/18 season. The 28-year-old says he had to leave the Blues because he ‘could not lose faith’ in himself.
The post read: “Some cycles begin while others end. My cycle at Chelsea began three years ago – three remarkable years in all aspects – and I will never forget it.
“Two championship titles, a Community Shield, 120 matches, 59 goals and 24 assists later this cycle has ended. Not the way I would have wanted – far from it – but the best way possible.
“The wonderful fans of such equally admirable club and all team mates, as well as all clinical, administrative and logistics staff will remain forever in my mind and in my heart.
“Will bring them with me with the certainty that I will always be by their side as well, and I’m sure they will understand the reason why this cycle of mine has now ended – because I could not lose faith in myself. Thank you Chelsea for everything!”
His registration into Atletico will come into effect on January 1, 2018, which means the Spaniard will have to miss all the group stage games in the Champions league for the Spanish club.