Hessenthaler - now manager of Dover - was captain on the Gills' first visit to the famous stadium 10 years ago, and then man of the match the following year when they beat Wigan 3-2 to win promotion to the second tier for the first time.
He then became manager after promotion and oversaw four seasons in the Championship before resigning in November 2004, but the club remains close to his heart.
And he told Kent Online: "Getting there has brought back memories for me and it's now the third time we have got to Wembley.
"I will be there cheering them on. Hopefully they will get promoted and it will be a great day.
"It would cap a great year for me personally because I am really enjoying myself at Dover, and it's going very well there. But to see the old club back at Wembley, and getting promoted, would be absolutely tremendous."