Arsenal have completed the signing of Spanish defender Pablo Mari from Flamengo, the club announced on Wednesday afternoon.
The 26-year-old has moved to Emirates Stadium on loan until the end of the 2019-20 campaign after completing a medical in London.
The Gunners have had to pay an initial fee of around £4.25 million, and have the option to sign the centre-back permanently in the summer.
Mari touched down in England with Arsenal technical director Edu at the weekend to iron out the final details of his move, but had to return to Brazil after a breakdown in negotiations.
However, the Gunners continued to pursue a deal and made a significant breakthrough in talks with Flamengo at the start of the week.
Mari was granted permission to return to London and finalise his switch to the Emirates, and could be in line to make his debut for the club this weekend.
The Gunners are currently without Calum Chambers while he recovers from a serious knee injury, and Shkodran Mustafi is likely to be out for a couple of weeks after sustaining a sprained ankle during Monday's FA Cup win over Bournemouth.
Mikel Arteta now has an extra option to consider at the back, with Mari joining David Luiz, Sokratis and Rob Holding in his defensive ranks.
Mari spent three years at Manchester City before joining Flamengo in 2019, but failed to make a single senior appearance for the reigning Premier League champions.
He reached his best form to date in Brazil, helping Jorge Jesus's side win the Copa Libertadores while also featuring in the Club World Cup.
The Spaniard will now be charged with aiding Arsenal's challenge for a top-four finish in the Premier League, with a tough trip to Burnley up next on Sunday.
If Arteta opts to leave Mari out of that fixture, he will not appear for the club until after the winter break.
Arsenal are set to travel for a warm-weather training camp in Dubai before returning to action on February 16, as Newcastle make the trip down to the Emirates.
The Gunners will then take in a Europa League round of 32 clash against Olympiacos four days later, with the first leg taking place in Greece at the Karaiskakis Stadium.