Chelsea have agreed a £6.6m fee with West Ham for midfielder Joe Cole.
The 21-year-old still has to agree personal terms and undergo a medical, but should he sign it will take Chelsea's spending so far this summer to £58m after the London club had a £15m bid accepted for Manchester United's Juan Sebastian Veron.
Both deals are expected to be concluded in time for the Champions League deadline on Thursday.
Under new Russian billionaire owner Roman Abramovich, Chelsea have lavished £37m on four players.
Damien Duff, Geremi, Wayne Bridge and former West Ham right-back Glen Johnson have all joined Abramovich's Stamford Bridge revolution.
Chelsea manager Claudio Ranieri was fulsome in his praise for Joe Cole after his side's 4-1 victory over Watford at Vicarage Road on Tuesday.
"Without Gianfranco (Zola), I need a player who can dribble - and I think Joe Cole is that kind of player," said Ranieri.
"He can play in any midfield position from the left to the right, or behind the front two.
"He's not signed yet but I hope he arrives. He's fantastic one-on-one. He's very clever and passes the ball very well.
"I like him when a match is close. He can dribble, pass and score a goal.
He's strong and an Englishman.
"When I arrived, I said I'd like a blend of young English players and
experienced players. Slowly, slowly, that is possible."
West Ham director Trevor Brooking had already revealed on Tuesday that the Hammers may be forced to make "one more significant sale" to finance the rebuilding of their own squad.
But Cole's exit from Upton Park will be the last sanctioned by the West Ham board this summer.
A West Ham statement read: "Everyone at the club is extremely sorry to see Joe leave Upton Park, but wish him the best of luck at his new club.
"This transfer now ensures that no further sales will be necessary following relegation. The priority will now be bringing players in to strengthen the squad."
Cole, who has been at West Ham since joining them as a trainee, admitted it was a wrench to leave Upton Park.
He said: "It's been a difficult decision but I feel it is time to leave West Ham.
"I still have great affection for the club and I would like to think that I could return here some time in the future."