Birmingham have signed defender Marc Roberts from Sky Bet Championship rivals Barnsley for an undisclosed fee.
Blues agreed a fee for the Tykes skipper on Friday and the 26-year-old Yorkshireman has now signed a five-year deal at St Andrew's.
Roberts becomes Harry Redknapp's second summer signing following the arrival of Brighton goalkeeper David Stockdale.
Birmingham's signing of Roberts suggests Redknapp has conceded defeat in his attempt to sign former England and Chelsea captain John Terry.
Redknapp had offered Terry a contract at Blues but it looks likely the 36-year-old centre-back, who officially became a free agent on Saturday when his contract at Chelsea expired, will sign for Birmingham's city rivals Aston Villa.
"I'm happy to be at such a big club," Roberts told BluesTV. "There's been a lot of rumours and a lot of clubs interested but when a manager like Harry Redknapp comes along and asks for your signature you've got to take it seriously.
"There are some really good players here and from my point of view I want to help the football club get promoted. That's the end aim.
"I pride myself on clean sheets. I'm a defender first and foremost. My job is to protect the goalkeeper and let the more technical players go and score goals.
"I'm a heart on my sleeve type of player. I'll give my all every game and I want to win. I'm addicted to winning and it can only be a good trait."
