We all have our favorite celebrities. Some we pine after, concocting fantasies that sometimes end like fairytales in "happily ever after."

But have you really, seriously considered what your baby with one-half of Brangelina, Scarlett Johansson or Jon Hamm when he's not pretending to run an ad agency would look like? To the legions of AKB48 fans, the fanciful thought will not require so much imagination.

"Will...