The Robins will be expected to reach round four after being drawn at home against League One opposition but Millen will leave nothing to chance.
Aware of City's poor recent record in the FA Cup - the club have gone out at the third-round stage in each of the last three seasons and last went beyond the fourth round in 1994 - Millen insists he will take the competition seriously.
"We are overdue a run in the FA Cup and I can assure our supporters we will be putting our strongest available side out," Millen told the club`s official website. "Some managers use the FA Cup to give fringe players a game but I am not going down that road.
"There are so many benefits to having a good FA Cup run, not least the money it can make for the club. We will be taking it as seriously as any other game we play in the Championship.
"We reached the fourth round and took Middlesbrough to a replay a few years ago but this club has not had an extended run in the competition for a long time and I want to try and put that right because it is still a big competition and it means a lot to the players and the supporters."
Source: PA
Source: PA