Chelsea defender David Luiz is set to join Arsenal in an £8m deal before the transfer window deadline, Sky Sports News understands.
Luiz will have a medical at Arsenal's training ground on Thursday and is expected to sign a two-year contract before the 5pm deadline, after a deal was agreed between the clubs.
The 32-year-old centre-back trained away from the rest of Frank Lampard's squad on Wednesday.
Arsenal head coach Unai Emery told Sky Sports News he wants to sign a centre-back before Thursday's deadline.
"If we can on the last day, we will try to sign another centre-back, but one who has the capacity to help us," said Emery.
"We have a lot of defensive players. Maybe, it is different when Laurent Koscielny tells us he wanted to leave.
"We tried to sign some important, expensive players for our defence. But when we can't do that, the second line players don't really convince us to sign them."
'Luiz could be a cracking deal'
Former Arsenal striker Charlie Nicholas thinks the Brazil international's arrival at the Emirates could prove to be a brilliant piece of business by the Gunners.
"He is an unpredictable player, a big personality, very talented. But never reliable and consistent enough as a defender," the Scot told SSN.
"But the facts are, if Arsenal are going to sign players who are better than they already are, then I'm all in. There is no problem in that for me. And David Luiz, even though he takes risks, probably fits the Arsenal criteria much better than what Arsenal currently have.
"Defensively, if they sign him, I think it could be a cracking deal for Arsenal."
Tierney fee agreed with Celtic
The left-back is on his way to London and looks set to sign ahead of Thursday's English Premier League deadline.
Agreeing personal terms is not expected to be a problem.
Follow Deadline Day on Sky Sports
It's Transfer Deadline Day for the Premier League and Championship on Thursday - and Sky Sports will be bringing you all the latest news on who your club is signing.
Start your day with Deadline Day Breakfast (6am) ahead of a special Good Morning Transfers show (9am), with Deadline Day - The Countdown (4pm) taking you to the 5pm deadline.
The Transfer Show - Deadline Day at 6pm will analyse the big moves before Deadline Day at Ten rounds up all the transfer headlines.