Willian will wearing the number 12 Jersey at Arsenal next season after completing a free transfer from Chelsea.
The 32-year-old has put pen to paper on a three-year deal with the Gunners, believed to be worth around £100,000-a-week.
Gunners head coach Mikel Arteta revealed his delight at getting the transfer for the 32-year-old over the line.
‘I believe he’s a player that can really make a difference for us,” said the Arsenal boss.
‘We have been monitoring him for the past few months, we had a clear intention to strengthen in the attacking midfielder and the winger positions [and] he is a player that gives us a lot of versatility.
Club technical director Edu added: ‘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.
‘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.’