Man City sign Palace defender Guehi
City stepped up their pursuit of the England international after suffering an injury crisis at centre-half.
Guehi, who came close to joining Liverpool on transfer deadline day in September, is City's second signing of the January transfer window after their capture of Ghana winger Antoine Semenyo from Bournemouth for about £65 million.
"I am really happy and incredibly proud to be a Manchester City player," Guehi said.
"This move feels like the culmination of all the hard work I have put into my career. I am now at the best club in England and part of an unbelievable squad of players.
"It feels good to be able to say that. I want to grow as a player and a person, and I know at this club that's going to happen."
City director of football Hugo Viana said Guehi had been "one of the best defenders in English football for quite some time now".
"I feel we have signed a huge talent who will help us improve," he said.
"He is only 25, but he has shown already he is a leader, a brilliant professional and someone desperate to improve."
The Chelsea academy graduate played 188 times for Palace after moving to Selhurst Park from the Blues in 2021.
He captained Palace to FA Cup glory against City in May -- the first major trophy in the south London club's history -- and has won 26 England caps.
Other teams reportedly interested in the defender, including Liverpool once again and Bayern Munich, were understood to be targeting a move at the end of the season, when Guehi would have been a free agent.
Pep Guardiola's City, dethroned as Premier League champions by Liverpool last year, are second in the table, seven points behind leaders Arsenal.
Central defenders John Stones, Ruben Dias and Josko Gvardiol all missed from Saturday's 2-0 defeat by Manchester United at Old Trafford.
The club are also still challenging for silverware in the Champions League, FA Cup and League Cup.
Guardiola has overseen an expensive rebuild of his squad over the past year, with a clutch of long-serving players exiting the club, including Kevin De Bruyne, Ilkay Gundogan and Ederson.