Former Blues centre-half John McGreal has returned to the club in a role coaching the U23s and development squads.
The 49-year-old was with the Blues between 1999 and 2004 and was a member of the team which won promotion to the Premier League at Wembley in 2000 and finished fifth in the top flight the following season, qualifying for the UEFA Cup.
McGreal is a close friend of manager Paul Cook from their days at Tranmere together and has been spotted at games and around the training ground on a number of occasions in recent months, which led to speculation that he might join the club as assistant manager.
The Liverpudlian joined Swindon as manager in the summer but left after only a month. Previously he spent four years as manager of Colchester.
Town’s new director of football operations, Gary Probert, told the club site: "We are delighted to welcome John to the club.
"His role will be supporting Kieron Dyer with the U23s, with a real focus on working with individual players alongside their development plans. John knows the club well and brings a wealth of experience to our set-up.”