Former Blues centre-half Tommy Smith has joined Town’s League One promotion rivals Sunderland until the end of the season.
Smith, 29, was a free agent having left MLS side the Colorado Rapids at the end of their season and had until recently been training with the Blues’ U23s.
In January he was linked with Wigan and Portsmouth while Paul Lambert ruled out a return to Portman Road.
"I know a lot about the club — the history and the fan base. I am delighted to be a part of it and hopefully I can help push the team up towards the Championship," New Zealand international Smith told the Black Cats official website.
"I’ve heard about the Stadium of Light and the atmosphere that is generated and I am just really excited to step out there for the first time and hopefully success can follow.
"I see myself as a leader on and off the pitch so hopefully I can use that to be a good addition to the squad.”
Sunderland were in need of defensive cover due to Bailey Wright suffering a season-ending ankle injury.
Wearsiders manager Phil Parkinson added: "Tommy can play anywhere across the back and, given Bailey Wright's injury, I wanted to make sure that we were not left short in the last three months of the season.
"Tommy is a very experienced player, he has played a lot of games in the Championship, and he will fit straight into our squad.
"He is a similar type of player to Bailey, and we think he will be a good addition.
"He will need a little bit of fitness work to get fully up to speed but he has been training so he is not far away.”