David Luiz has completed a shock move from Chelsea to Arsenal in an £8 million ($10m) deal.

The Brazil international will sign a two-year deal at the Emirates Stadium and is their second defensive signing on deadline day, joining Kieran Tierney as a new face in the Gunners backline.

The north London side have made a third addition defensively, signing William Saliba from Saint-Etienne, but sent the 18-year-old straight back to the French club on loan for the 2019-20 season.

David Luiz may be at the other end of his career from Saliba, but has lots of Premier League experience, racking up 160 appearances in the league for Chelsea over two spells at Stamford Bridge.

And Arsenal manager Unai Emery welcomed his new charge to the club, highlighting that experience.

“David has huge experience and I look forward to working with him again. He is a well known player and adds to our defensive strength,” the Spaniard said on the club’s official website.

Emery and David Luiz worked together while they were both at Paris Saint-Germain, where the centre-back spent two seasons, in between his stints at Chelsea.

The 32-year-old won the Premier League, three FA Cups, the Europa League and the Champions League with Chelsea, with whom he only signed a new two-year deal in May.

He has also won 56 caps for Brazil but has not played for his country since 2017.

Luiz and Tierney join Nicolas Pepe, Dani Ceballos and Gabriel Martinelli at the Emirates Stadium after a busy transfer window for their new club.

Pepe joined from Lille for a club-record fee of £72m ($87m) on August 1.

Arsenal’s transfer budget was widely reported to be around £45m, but the capture of Pepe refuted that.

Despite the signing of the Ivory Coast winger along with Real Madrid loanee Ceballos, who plays in midfield, many Arsenal observers were concerned that Emery had not strengthened in defence.

Those concerns were amplified when club captain Laurent Koscielny agitated for a move away, finally being transferred to Bordeaux on August 6 for £5m.

The surprising swoop for David Luiz, and the long-anticipated arrival of Tierney, may go some way to assuaging those fears as Arsenal look to return to the Champions League after a three year absence.

The Gunners open their Premier League campaign with a game away at Newcastle on August 11.