Willian has confirmed he is leaving Chelsea, with Arsenal close to completing his signing on a three-year deal.
The 32-year-old leaves Stamford Bridge at the end of his contract after a seven-year spell, with Chelsea only willing to offer him a two-year deal rather than the player's desired three years.
He wrote an open letter to fans confirming his exit following Chelsea's defeat to Bayern in the last 16 of the Champions League.
"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 wrote.
"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.
"Yet, beyond the trophies, I learnt a lot about myself. I developed a great deal, becoming a better player and a better person.
"With each training session, with each game, with every minute spent in the dressing room, I was always learning.
"I am really grateful to the Chelsea fans for the affectionate way they welcomed me at Stamford Bridge and their support throughout my time at the club.
"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!
"The time has now come to move on. I am certainly going to miss my team-mates. 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!
"My heartfelt thanks go out to all of you and God bless you!"
Arsenal in pole position to sign Willian
Arsenal moved into pole position to sign the Brazil international by offering a three-year contract earlier this week, and are on the verge of beating off competition from Barcelona and Inter Miami.
Along with the length of the deal, joining Mikel Arteta's rejuvenated side and the chance to work with fellow Brazilian Edu are the reasons Arsenal are favourites to secure Willian's signature.
Chelsea head coach Frank Lampard has insisted he will have no hard feelings if Willian leaves the club.
"It actually doesn't matter about disappointment from any party in this situation," said Lampard, ahead of Chelsea's Champions League tie against Bayern Munich on Saturday.
"I haven't got an answer for you (if Willian will leave) first and foremost, because Willian remains our player at the moment.
"In terms of being disappointed, certainly as a club I think we have done everything we can to explain to Willian, and mine and his relationship is really close."
Willian made 47 appearances for Chelsea in all competitions and finished the season in fine form, with four Premier League goals after the restart taking his tally for the season to nine.
Analysis: 'Willian wants one last big deal'
Sky Sports News' Kaveh Solhekol:
"Willian wants one big final contract - ideally a three-year deal to take him to 35. Chelsea would like to keep him, though they're not going to offer him three years.
"At the moment, it looks like Arsenal is his most likely destination but he is a free agent and at his age, realistically, you're likely to go where there is the most money and longest contract on offer.
"He's got a great injury record so his agent will be saying, 'Don't worry about his fitness'."
Arsenal's pursuit of Willian comes as they attempt to seal a new deal for captain Pierre-Emerick Aubameyang, who is understood to be close to extending his contract, which is currently set to expire in the summer of 2021.
Aubameyang, 31, scored 22 goals in the Premier League last season and netted twice in Arsenal's 2-1 win over Chelsea in Saturday's FA Cup final.
Since his move to Arsenal from Borussia Dortmund in January 2018, he has scored 54 goals in 85 Premier League games.
The news of the Arsenal's offers to Aubameyang and Willian comes after the club made a statement revealing their plan to make 55 members of staff redundant, including international recruitment specialist Francis Cagigao.
Arsenal, who will hold meetings with staff on Friday, said one of the key reasons cutbacks are being made is to "maintain investment in the team".
Summer transfer window - key dates and times
The summer transfer window will run for 10 weeks from July 27 and close at 11pm on October 5.
A domestic-only window for trades between the Premier League and EFL then runs from October 5 and closes on Friday October 16 at 5pm. Follow all the news and analysis on Sky Sports News and across Sky Sports' digital platforms, including with our dedicated Transfer Centre blog.