Defender Ridgewell made the switch from Villa Park to St Andrews three years ago and immediately became a supporters' favourite. Now former England Under-21 player Gardner has signed a four-and-a-half-year deal with the Blues through to the summer of 2014, although he is not eligible for tonight's Barclays Premier League clash at Chelsea.
Ridgewell said: "Are there problems switching from Aston Villa? To be honest, with me, everyone has been quite good about it. I'm a London boy and everyone knew that when I came across."
He added: "I've spoken to Villa fans when I've been out and they understood that I moved for football reasons and I think the Blues fans have seen the way I've gone about my game playing for Birmingham and there's been no problems.
"I wasn't the first to move to Birmingham and I think, if you go about it in the right way, the fans respect that.
"I remember when I came here one of the masseurs told me that as long as you give everything, tackle people and are committed, the fans would love you.
"If Craig does that and plays well every week, then I'm sure they will love him here."
Ridgewell has played a significant part in Blues putting together a 15-match run but knows Chelsea will provide a massive threat to ending that sequence.
He said: "It's a big test. We're all looking forward to it playing against all those stars. We've got to give them respect - but they've got to give us respect too as we're undefeated for so long and playing well.
"With any luck, hopefully we will stay unbeaten. It's a difficult task to go down to Chelsea and beat them but we will give it a good go."