It's finally happened, Gooners.
The defender has arrived in a deal reportedly worth £25m and has signed a five-year contract with his new club.
Gabriel arrived in London last Monday but had to wait to put the finishing touches on the move due to coronavirus quarantine rules.
He will now have to self-isolate for 14 days before linking up with his new teammates.
Mikel Arteta has now recruited two quality centre-backs from Ligue 1 this summer, causing plenty of excitement for the club's supporters.
The club have also signed fellow Brazilian Willian and completed permanent deals for Pablo Mari and Cedric Soares.
Speaking about the signing, Arsenal's technical director Edu said: "We are delighted to have signed Gabriel. He is a player we have been studying for a while and he was in demand from many clubs, so we are proud to have agreed and completed this transfer with Lille and the player.
"Gabriel is a player of high quality and Mikel and his coaches are looking forward to integrating him into the club."
@biel_m04 will wear the number shirt!
Ready to rep our new signing?
— Arsenal (@Arsenal) September 1, 2020