The new Stones boss has made his fourth signing since taking over from Bobby Wilkinson.
Midfielder Connor Smith has arrived from Billericay Town.
The 26-year-old is no stranger to the club’s fans - he was on loan from Watford back in 2012.
Brennan knows exactly what the former Plymouth and Wimbledon man will bring.
The Irishman said: “He is a player that will provide our midfield with athleticism and we know Connor can score and create goals from central midfield.
“He has plenty of experience and he knows our club well."