Midfielder Darren Ambrose has joined Colchester United on a one-year deal.
The 31-year-old had been training with the Blues during pre-season, looking to win a new contract having joined Town for a third spell last season.
Colchester manager Tony Humes said: "We're pleased to have Darren here and he gives us that experience and a bit of variation in terms of the positions that he can play and how he fits into the system.
"Darren has had a good career playing at Premier League and Championship level so he's got that quality and that experience.
"There's a variety of positions he can play in, whether it's outside or inside but first and foremost the wide position was one we were looking for with the player we failed to get in so that's probably where he'll start."
Ambrose, a product of the Blues’ Academy, who also returned for a loan spell while with Charlton, made three starts and five sub appearances for Town last season, netting his only goal in the 1-1 FA Cup third round draw at Southampton.
The Harlow-born midfielder previously played for the U's in a pre-season friendly against Town last summer.