Every week, we tuned into “Dancing with the Stars” to watch Romeo strut his stuff — shirt open, flaunting those sexy abs — thinking, “Oh my, have you grown!” It seems as if he and Bow Wow went from “Lil” to grown and sexy overnight, and Tristan Wilds and Lee Thompson Young went from cute to foiine in the blink of an eye. This morning, let’s take a look at a few of our favorite child stars who have grown into heartthrobs….