Arsenal have completed the signing of David Luiz from Chelsea on a two-year deal for a fee of £8m.
The Brazilian centre-back, who made 248 appearances for Chelsea across two spells with the club, underwent his medical on Deadline Day after the two sides agreed a fee.
Luiz trained away from the rest of Frank Lampard's squad on Wednesday after indicating he wanted to leave the club.
"David has huge experience and I look forward to working with him again," Arsenal head coach Unai Emery said.
"He is a well known player and adds to our defensive strength."
The 32-year-old is Arsenal's second Deadline Day signing after they completed a £25m deal for left-back Kieran Tierney from Celtic.
David Luiz: Did you know?
- Last season: 36 PL apps/3 goals last season (36 starts) – his most apps, goals and starts in a PL season
- Most clearances (144) for Chelsea in PL last season
- Only European career red card for foul on Sead Kolasinac in 0-0 PL draw v Arsenal (H), Sept 2017
- 57 caps/3 goals for Brazil – last cap v Australia, June 2017
- Won 2019 EL with Chelsea – started 4-1 final win v Arsenal (Baku)
- Won 4 major trophies with Chelsea – 2 EL, 2012 CL and 16-17 PL
- The only player in Chelsea history to have played in 3 European trophy final wins (Gary Cahill also has 3 medals, but only played in 2 finals)
- Former Chelsea team-mate of Frank Lampard – started 2012 CL final win together
Arsenal had been left short at centre-back after the departure of former captain Laurent Koscielny, who shocked the club by demanding a transfer with a year left on his contract.
Luiz began his first spell at Chelsea in 2011, before returning to Stamford Bridge in 2016 after a two-year spell with Paris Saint-Germain.
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'Luiz is a winner'
Speaking on The Debate on Sky Sports, former Tottenham manager Tim Sherwood said Luiz will help to strengthen Arsenal's defence.
"I think Arsenal do need David Luiz, they certainly need to strengthen in the centre-back area. He is a proven winner in the Premier League, he's won multiple league titles and he's winner wherever he's gone. The manager knows him - Unai Emery worked with him at PSG - and he obviously feels like he can bring him into Arsenal and he can help strengthen them, which I think he will.
"Luiz's family are settled in London, they wont have to move, he still gets a big London club in Arsenal and it works for both parties. Frank Lampard will be the happiest out of everyone because he doesn't have a disgruntled player in his dressing room, he's got a player who he has moved on to another club - albeit a rival."