West Ham are on the verge of signing defender Kurt Zouma from Chelsea.
The 26-year-old centre-half is currently undergoing a medical in France after the clubs agreed a deal reportedly worth £25million.
Hammers boss David Moyes has been searching for defensive reinforcements all summer and appears to have finally got his man.
"We lost Fabian Balbuena last season and three centre-backs is not enough," said Moyes.
"We have had an offer accepted from Chelsea for Kurt but I could not tell you if the medical has been completed yet."
Blues boss Thomas Tuchel also confirmed a deal was close.
He said: "There are negotiations between West Ham and Chelsea about Kurt.
"Kurt right now is not with us but not because of these negotiations.
"He's had some personal and family issues and we allowed him to travel to France.
"There are negotiations but, to be very honest, I don't know where that leads right now.
"Those things can happen at this stage."