London: Willian says he is leaving Chelsea with "his head held high" ending a seven-year spell with the Premier League club he told fans in an open letter on Sunday.
The 32-year-old Brazil winger has been linked with a move to Arsenal after he failed to agree a new contract with the Blues.
Willian rejected Tottenham Hotspur to join Chelsea from Russian outfit Anzhi Makhachkala for £30 million ($39 million) in 2013.
He scored 63 goals in 339 appearances and won five trophies, two Premier League titles, an FA Cup, a League Cup and the Europa League.
However, an ankle injury prevented him playing in the FA Cup final loss to Arsenal and Saturday's Champions League last 16 second leg thumping by Bayern Munich.
"The time has now come to move on. I am certainly going to miss my team-mates," he said.
"I will miss all the staff at the club who've always treated me like a son and I will miss the fans.
"I leave with my head held high, safe in the knowledge that I won things here and always did my best in a Chelsea shirt."
Willian " a member of the Brazil squads at the 2014 and 2018 World Cup finals " said he had never regretted his preferring Chelsea to London rivals Spurs.
"They were seven wonderful years. In August 2013 when I received the offer from Chelsea, I was convinced that this was where I had to play," he said.
"Today I am certain that it was the best of decisions. There were so many happy times, some sad, there were trophies and it was always very intense.
"There was also criticism, which is normal, what is important though is that both the affection and criticism drove me to always give my all in every training session, every game, to be constantly improving until my very last minute in a Chelsea shirt."
Willian leaves along with fellow veteran Spain winger Pedro, who is joining AS Roma on a free transfer.
The 33-year-old European championships and World Cup winner also issued a heartfelt farewell message as he brought the curtain down on his half a decade spell at the club.
"After five wonderful years my stage at Chelsea FC comes to an end," he wrote on Instagram.
"It's been a pleasure and an honour to play for this club and win the Premier League, FA Cup and Europa League titles, as well as competing in one of the world's best football leagues.
"I made the right choice, I take with me wonderful and unforgettable memories."