My Singing Monsters has lured millions of users with its entrancingly catchy melodies, adorable creatures, and, most importantly, addictive world-building. (Must…hatch…singing wowng. Must…buy…rhythmic rock. Must…upgrade…castle. Wait, how has an hour gone by?) But after a year of mesmerizing kids—and more than a few adults who thought they had better things to do—on charm alone, the online game’s islands full of doo-wopping, drumming, and la-la-la-ing monsters will get their first celebrity guest: Kristian Bush, the male half of country-music stars Sugarland. Look for Bush’s monster in the game starting July 29.