The two-hour showcase will kick off at midday and is free to anyone that attends. Wristbands will be handed out in store from 9am next Friday morning.
The first 300 people to buy the PS2 game at the event will receive a CD soundtrack featuring five songs from FFXII, while the first 100 will also be given an exclusive Moogle soft toy.
A competition to win a trip for two to Japan will also be on offer.
And, just for fun, FFVII publisher and HMV will be handing out extra goodies to the fans wearing the best Final Fantasy costumes.