The 32-year-old’s arrival was confirmed on the Gunners’ Twitter account on Friday morning as he signs a three-year contract and is handed the no 12 shirt.
It came as Sportsmail revealed the incredible amount Willian will earn at his new club in the wake of 55 members of staff being made redundant this month.
Though Willian’s basic salary is lower than he earned at Chelsea, when bonuses, a signing-on fee and loyalty payments over the three years are included, it will amount to £220,000-a-week or around £35m over the course of his contract.
He said: ‘[I like] the way they play, everything is amazing – the stadium, and I think that with Arteta, Arsenal have a great opportunity to fight again for titles in the Premier League and in Europe so I’m very happy because of that.
‘I’m excited to start. I can’t wait to go on the pitch and do my thing to help my team-mates and to help this club to shine again. That’s what I want.
‘When I talked to [Mikel], the conversation was good, he gave me confidence to come to Arsenal. He said a lot of good things to me and that’s why I have come to Arsenal. ’Arteta said: ‘I believe he’s a player that can really make a difference for us.
‘He has the experience of everything in the football world but to still have the ambition to come here and contribute to bring the club where it belongs.
‘I have been really impressed with all the talks I have had with him and how much he wanted to come.’ Gunners Technical director Edu said: ‘I know him very well, since a long time ago because we’ve been working together for the Brazilian national team and of course I was following him because he played for another club.
The Brazilian winger poses with an Arsenal home shirt after completing his move to the club
‘He has a lot of fantastic attributes as a person, as a football player of course, his character.
‘I’m 100 per cent sure that everybody in the dressing room, the fans, myself and Mikel will enjoy having Willian in our side.’
The vast sums involved raise questions after Arsenal’s announcement last week that they are proposing to make 55 members of staff redundant.