Arsenal transfer news: David Luiz having medical on deadline day, plus Kieran Tierney, Sami Khedira and Eddie Nketiah latest

Arsenal have agreed an £8m fee with Premier League rivals Chelsea to buy the Brazilian defender on top of the move for Celtic left-back Tierney

David Luiz is undergoing a medical at Arsenal's training base ahead of a surprise move across London after the Gunners agreed an £8m fee with Premier League rivals Chelsea.

Luiz emerged as a shock candidate to replace former club captain Laurent Koscielny, who left the club for Bordeaux in acrimonious circumstances this week, and is set to complete a move across London for £8m, according to the BBC.

Sky Sports adds that the Brazilian has already arrived at the club's London Colney training base to undergo a medical.

The 32-year-old has already agreed terms on a two-year contract and could be parachuted straight into the team for Arsenal’s first game of the new season, against Newcastle United at St James’ Park on Sunday.

However, their planned move for RB Leipzig Dayot Upamecano is off as a result of the move for Luiz, with the Bundesliga side rejecting a £50m offer for the French centre-back and demanding in excess of £80m.

One player who is all-but-set to be unveiled as an Arsenal player though is Celtic left-back Kieran Tierney.

The Scotland international has been on the club’s radar for several years and will finally complete his move after protracted negotiations between the two clubs ended on Wednesday with the agreement of a £25m.

Tierney travelled to London on Wednesday and is also undergoing a medical at London Colney, with the club poised to announce their acquisition of the 22-year-old.

The full-back is expected to sign a five-year contract and will become the Gunners’ fifth summer recruit, following Nicolas Pepe, Gabriel Martinelli, Dani Ceballos and William Saliba.

Sami Khedira remains another potential deadline day signing, with the Juventus midfielder reportedly turning down offers in order to ensure a move to Arsenal goes through.

Tierney is poised to leave Celtic for Arsenal (Reuters)

Arsenal forward Eddie Nketiah is set to join Leeds United on loan for the season. The 20-year-old will replace Kemar Roofe who joined Anderlecht for £6.4m earlier this week.