Allen was struck by the positive attitude of a post office worker called Donna who asked him for his autograph before the recent match against Port Vale.
But rather than just thank her and move on, Allen decided to tap into Donna's enthusiasm by asking her to get his team fired up for the match.
"She bubbled and oozed happiness and a positive attitude, so I took her into the dressing room and introduced her to all the players," Allen wrote in the club programme at the weekend. "Then she gave a speech, or team talk, to the players from a supporter's perspective.
"She told them all they were great, she told them all to play the way you have been and she told them all we would win 2-1."
Donna was wrong on that last count: the inspired Gills actually won the match 2-0, their latest success in a run of good matches which has seen them pick up 26 points in the last 11 matches to build a three-point lead at the top of League Two.
The inspirational fan - who told Allen she never misses a match and had travelled down to the game on the train - was then invited to travel back to Kent on the team bus rather than get the train.
And she grabbed the opportunity with both hands, even pinching the manager's seat when he was dropped off early on the trip home!