Neil Danns has finalised his move from Colchester to Birmingham after penning a three-year deal.
The 23-year-old sealed the deal after Birmingham struck a £500,000 deal with the Essex outfit.
"When a club the size of Birmingham come in for you, it's hard to say no," he told the club's official website.
"There is so much prestige about the club and the quality of players that are here, it's a great opportunity for me.
"The fans are so passionate here and you can see the ambition with the signing of Cameron Jerome.
"They are rebuilding the squad here with young, ambitious players and for me to be a part of that is a great opportunity. I'm just looking forward to it so much.
"My time at Colchester has been absolutely tremendous and I couldn't have asked much more from the club.
"The fans, all the players and the staff at the club were great.
"But there comes a time in everyone's career that you want to test yourself and move to the next step.
"I think Birmingham will be back in the Premiership before too long because the talent and potential is here.
"I have come here to further my career. The hard work starts now but I am ready and willing to put everything into what hopefully will be a promotion-winning season for Birmingham."