Bolton and England defender Gary Cahill has completed his move to Chelsea.
Bolton accepted an offer from Chelsea for the 26-year-old central defender before the transfer window opened, but protracted contract negotiations delayed the deal. Chelsea have not revealed the length of the contract.
Cahill, who has been given the No. 24 shirt, told the club's official website: "Chelsea is a massive club, it is a club that looks to win trophies season in season out and it is a big opportunity for me to be a part of that. Opportunities like this you can't turn down."
While on Bolton's website, he said: "This is the right move for me at the right time and I would like to thank everyone at Bolton because I've had a great four years at the football club.
"My spell with Wanderers has enabled me to break into the England squad, and I would particularly like to thank the fans for their support along the way.''
Newspaper reports suggest Cahill is set to earn £23 million in wages and bonuses over a suggested five-year deal at Stamford Bridge.
Cahill was said to have initially wanted £100,000-a-week from Chelsea, and the club were unwilling to meet his demands. But talks with Chelsea's chief executive Ron Gourlay on Thursday are thought to have led to an agreement that will see Cahill take home around £80,000-a-week.
It is now expected that Cahill will be available for Chelsea's Premier League game against Norwich at Carrow Road on Saturday, while he is eligible for the Blues FA Cup tie at Milton Keynes Dons or Queens Park Rangers having been left out of Bolton's FA Cup tie at Macclesfield earlier this month.
Meanwhile, Owen Coyle has confirmed Bolton are hoping to finalise a deal to sign USA international Tim Ream as Cahill's replacement.
"He is a player that we would love to bring to the football club and hopefully in the next few days that can come to fruition," he said.