Well, I got schooled!
But just to clarify, when I said "stars", I wasn't necessarily talking about every child who's been in a sitcom or TV series. I meant ones who became and stayed household names at a really young age, more like the Mickey Rooney mold.
I'm not even sure Bieber qualifies per my specs. (That's because I don't know how old he was when he became famous). I do think it's different with teens, who at least have some kind of worldview based on reality.