Town have announced that right-back Josh Emmanuel has put pen to paper on a contract which runs until June 2019 with an option for a further season.
The 19-year-old has made eight senior starts and three sub appearances for the Blues, so far without scoring, having made his debut on the opening day of last season at Brentford.
"I’m obviously delighted to have signed a new contract,” the academy product told the club site.
"I’m enjoying life, enjoying my football and I want to keep on improving my game.
"The gaffer, TC, Bryan Klug and the academy staff have been great to me in my time at the club and have really helped me progress. I just want to keep that going now, the progression.
"It’s about being more consistent in my performances and doing what I need to do to be ready when I am called upon.”
The London-born, Essex-raised defender joined the Town academy as a schoolboy after leaving West Ham's youth set-up.
Emmanuel, who spent time on loan at Crawley last season, making one start and one sub appearance, looks set to return to the Town team facing Nottingham Forest after the international break with skipper Luke Chambers expected to move to centre-half to cover for Adam Webster, who has a groin injury.