Arsenal have completed the signing of Brazilian defender Gabriel Magalhaes from Lille for 26m euros (£23.14m).
The 22-year-old, a left-footed centre back, made 34 appearances in all competitions for Lille last season as they finished fourth in Ligue 1.
He joins the Gunners on a long-term contract.
"He is a player we have been studying for a while and he was in demand from many clubs," said Arsenal technical director Edu.
"Gabriel is a player of high quality and Mikel (Arteta) and his coaches are looking forward to integrating him into the club."
Arsenal boss Mikel Arteta said: "We welcome Gabriel to Arsenal. He has many qualities which will make us stronger as a defensive unit and as a team.
"He has proved with Lille he is a defender with many outstanding attributes and we are looking forward to watching him grow as an Arsenal player."
Gabriel said he considered offers from a number of clubs before deciding to join Arsenal.
"It was a very surreal experience, there were offers coming from a few different clubs," he said.
"I spoke a lot with my family and my agents, I also spoke with some of Lille's directors but, as I said, this club's history and traditions and the team project for the next few years were very motivational for my decision to come here.
"So here I am, wearing the Arsenal shirt - I will give my best for it."
BBC World Service's John Bennett
Although it took him a relatively long time to make an impact at Lille, Gabriel left a big impression on the French club after some very impressive performances over the last 18 months.
I spoke to the club's president Gerard Lopez for a BBC World Service radio show recently and he was full of praise for the defender on and off the pitch. Lopez talked about his physical presence and his power but also his pace and his "great pass quality". He also told me that Gabriel is close to getting a call-up to the senior Brazil national team.
Meanwhile, Kieran Tierney will enjoy playing next to him because by all accounts he's excellent at covering behind an attacking full-back and, unlike some centre-backs, is very comfortable when he's forced into wide areas.
It may take Gabriel a little time to adapt to the Premier League but for Lopez there were no doubts about his ability: "He's got so much talent and physical presence that he could succeed anywhere."
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