But was Michael Jackson really singing Prince's "Let's Go Crazy"?

As for "fair use", does that apply in this case? I suppose if the judge says it does, then it does. Or maybe the parody defence is applicable. On the other hand, it sounds as though the entire Universal music catalogue can be put on YouTube by filming a baby reacting to it. Surely some mistake? (And of course once you were done, the baby would be out of high school...)

really mike...?

a video ... on the radio