Arsenal have confirmed the signing of defender Gabriel Paulista from Villarreal for an undisclosed fee.
The Gunners have refused to reveal the length of the deal that the 24-year-old Brazilian has penned.
It is understood that Arsenal have paid around £15m for the centre-back, who was granted a work permit on Monday.
The deal has seen striker Joel Campbell move the other way on loan, with the Costa Rica international agreeing "a new long-term deal" at the Emirates Stadium ahead of his departure to Spain.
"A while ago I had a really huge desire to play in the Premier League, so since that point I put it in my head that I really wanted to do it," Gabriel told Arsenal's official website. "I had a talk with my family and I told them that it was my dream to play in the Premier League. Getting here to such a big club is so gratifying.
"I am arriving at a big club and the fans can expect to find a Gabriel with a great will to help everyone. Not just thinking of me as an individual, because to me that is not important. I care more about helping the team and my teammates."
Gabriel, who leaves Villarreal following an 18-month spell at the La Liga club, is yet to represent his country at senior level.
