Arsenal beat off competition from Manchester United, Everton and Napoli for 22-year-old centre-back
Arsenal have signed Brazilian defender Gabriel from Lille for £27m on a long-term contract.
Manchester United, Everton and Serie A club Napoli had all held an interest in centre-back Gabriel, who made 34 appearances in all competitions last season as Lille finished fourth in Ligue 1.
The 22-year-old bolsters Arsenal head coach Mikel Arteta's options in defence that will be further boosted by William Saliba, who spent last season on loan at St Etienne following his £27m signing from the French club last summer.
Gabriel, who played in all six of Lille's Champions League group stage matches last season, is Arsenal's second major summer signing following compatriot Willian's move from Chelsea on a free transfer.
Pablo Mari and Cedric Soares made their loan moves permanent from Flamengo and Southampton respectively earlier this summer.
Gabriel is the second player to join Arsenal from Lille in the past 12 months, following Ivory Coast international Nicolas Pepe's move to the Emirates for a club-record £72m last summer.
"We welcome Gabriel to Arsenal," Arsenal boss Mikel Arteta told the club's website. "He has many qualities which will make us stronger as a defensive unit and as a team.
"He has proved with Lille that he is a defender with many outstanding attributes and we are looking forward to watching him grow as an Arsenal player."
Technical director Edu added: "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."
When will Gabriel be available?
Sky Sports News’ chief reporter Bryan Swanson:
One issue Arsenal are going to have to sort out is this issue regarding self-isolation for anyone coming back into the UK. The government has confirmed to us at Sky Sports News that people coming back into the UK do have to go into quarantine for 14 days if they arrive from countries not in a travel corridor. So, that includes players from France etc. They are being treated no differently to anyone else, any other member of the public.
There might be a bit of confusion here as people saw Liverpool over in Austria but that is because there is a team exemption as they are playing games. But with transfers, you are going to have to sit tight and self-isolate. You are going to have to stay safe along with everyone else and that will be a factor and a consideration for all clubs.
Analysis: Why Gabriel Magalhaes was so sought after
Sky Sports' Nick Grounds takes a closer look at the defender:
Gabriel started his career at Avai, a side who currently play in the second tier of Brazilian football.
After 21 appearances, he made the move to Europe in January 2017, signing for Ligue 1 side Lille for a fairly modest fee of £1.5m.
Gabriel initially struggled to adapt to senior football at Lille and went out on loan twice. First to Troyes, where he spent the first half of the 2017/18 season, before a temporary move to Dynamo Zagreb in January 2018.
First-team opportunities continued to evade him, moving between the reserve and senior sides before returning to Lille for the start of the 2018/19 season.
Gabriel took his time to cement himself in the side, not starting a Ligue 1 game until February 2019. But he has not looked back since; forging a relatively successful partnership with former Southampton player Jose Fonte at centre-back.
After a seven-year absence, Gabriel helped Lille qualify for the Champions League in 2018/19, finishing second in Ligue 1 to PSG.
Gabriel continued his ascent last season, with a string of impressive performances both domestically and in the Champions League.
Analysis: 'Edu a big draw for players'
Sky Sports News' Kaveh Solhekol:
We have seen Raul Sanllehi leave the club and now what we see is this axis at Arsenal where the power, when it comes to football, rests with Edu and Mikel Arteta.
They are obviously working very closely together, and I think Edu has got a big draw. Of course, he wasn't the manager of the Brazil national team, but he oversaw that team for a few years. If you are a Brazilian player and Edu calls you and says: "Come to Arsenal, look what I achieved at Arsenal. Everything is here for you to develop as a player."
It's difficult to say no to him and that's why we are seeing Arsenal sign these kinds of players.
Lille president: Gabriel a real fighter
Lille president Gerard Lopez spoke to Sky Sports News about Gabriel's move before it was formally agreed, and said the Brazilian is "at the start of something big" in his career.
"He is a great kid and that is one of the most important things," Lopez said. "He didn't have an easy start with us given the fact that the coach at the time didn't trust him because of his age.
"He is a real fighter and has immense physical presence but knows how to use it smartly. He is still raw and I know the Brazil national team are looking at him very seriously for the A-team.
"I think he is at the start of something big, and he does everything to succeed."
Transfer Talk: Arsenal's defence sorted for a decade?
Gabriel Magalhaes could form a defensive partnership with William Saliba at Arsenal for "the best part of 10 years", French football expert Jonathan Johnson told the Sky Sports Transfer Talk podcast.
"It would be a pairing of two very good, very promising central defensive talents and potentially a partnership which could serve Arsenal for the best part of the next 10 years," he said.
"Saliba's season with St Etienne was mixed, obviously the Ligue 1 season was brought to a premature close because of the Covid crisis, he had a few injuries as well and it was a shame he was not granted the chance to play in the Coupe de France final before finishing his loan spell, it would have been a good way for him to go.
"But he's shown when he plays he has a lot of talent, a lot of potential, he is fulfilling quite a bit of that already, he has impressive maturity for his age, and I think he would pair well with Gabriel.
"Both will take a bit of time to get used to the Premier League but both are tailor-made for Premier League football. I do not think that process would take as long as it would with other foreign players."
Sky Sports News reporter Dharmesh Sheth, speaking to The Transfer Show:
Gabriel's arrival means Arsenal have nine central defenders on their books.
Konstantinos Mavropanos has already sorted a loan move to Stuttgart for next season.
David Luiz recently signed a contract extension, Pablo Mari recently made his loan deal permanent and William Saliba will join after spending last season on loan at St Etienne. Add to that Rob Holding, who has got three years left on his contract, and you would expect Mikel Arteta to choose from those four players, plus Gabriel.
That leaves Calum Chambers, Sokratis Papastathopoulos and Shkodran Mustafi. Chambers has got two years left on his current deal and his versatility may convince Arteta that he's got a role to play at Arsenal still.
The same can't be said for Mustafi and Sokratis. Both have entered the final year of their contracts at the Emirates Stadium. It's difficult to see how they'd get game time, so, they might want to cash in now. It's easier said than done though because Mustafi is currently injured. So, who would buy him at this stage?