Pre-teen Willow and Justin Bieber are preparing to join forces for a teen music invasion. The "Whip My Hair" singer just announced via her Twitter that she will be the opening act for the European leg of Bieber’s "My World" tour. This isn’t the first time Bieber has worked with someone from the Smith clan. Earlier this year Jaden Smith (Willow’s older brother) teamed up with Justin for "Never Say Never," the theme song to the remake of The Karate Kid. At this rate, it seems that these kids are well on their way to achieving world domination by, I'd say, 18 years old. Not bad.