Are Functionalists just simply another version of (philosophical) Behaviorists?

In the context of the philosophy of mind, a prominent question has arisen that frequently comes up during lectures in my philosophy of mind cl. Is functionalism just another version of behaviorism? Or is there a meaningful distinction between the two, separating them as distinct or opposing schools of thought? I need an (educated) opinion, because I am having a hard time deciding for myself what I think about this issue. Its important because my prof has hinted a few times that it will be a question on our midterm examination.