Birmingham have signed former Arsenal midfielder Alexander Hleb, Czech defender Martin Jiranek and Chile winger Jean Beausejour.
On a busy deadline day at St Andrews, Hleb, 29, joined on a season-long loan from Barcelona and Jiranek, 31, on a one-year deal from Spartak Moscow.
Beausejour, 26, signed a three-year contract for an undisclosed fee.
"Hleb is a top quality player - one who at one stage we'd only actually dreamed about really," said boss Alex McLeish.
"This is a major signing for us and we are very happy to have him here."
Hleb made 89 appearances for Arsenal before leaving the club to join Barcelona two years ago.
The Belarus international struggled to hold down a first-team place at the Catalan giants and spent last season on loan at German side Stuttgart.
"Over the past year or so we have talked about him but with no real belief we could get him," said McLeish.
"We decided to give it a try and towards the end of the window we found out it might be possible."
Jiranek is a 6ft 3in centre half with 31 caps for the Czech Republic, who he represented in the 2004 European Championship and 2006 World Cup.
"Jiranek has tremendous experience on club, European and international fronts," said McLeish, who has also added Ben Foster, Nikola Zigic, Enric Valles and Matt Derbyshire to his squad in the close season.
"He is a good presence and his arrival will keep Roger Johnson and Scott Dann on their toes."
Beausejour, who helped Chile reach the last 16 of the World Cup, has signed from Mexican side Club America.
"He has been on our list of targets for a long time because he is strong and quick with the ability to beat his man and get crosses in," said McLeish.
Birmingham missed out on defensive target Armand Traore, with the Arsenal left-back choosing to join Juventus on loan.
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