AKB48′s Yuko Oshima will not only star in Final Fantasy XIII-2′s commercial in Japan, but will also be co-designing costumes for the game, specifically for Serah. The commercial will feature her proposing her designs to the development team while in a meeting.
As soon as the commercial broadcasts on November 15, the official test play site will hold a popularity contest on the 2 costumes that Oshima designed. The costume that wins the most popularity will be used in the game.
Although she has also designed costumes for the moogle, the actual DLC will only include the costume for Serah as the moogle outfits are just for show.
Source: Andriasang