In the late 1960s, the term supergroup was coined to describe "a rock music group whose performers are already famous from having performed individually or in other groups." While the term is also used in a broader sense, to describe any "highly successful rock group", this article focuses on the first definition. Supergroups tend to be short-lived, often lasting only for an album or two, perhaps because of the conflict of egos between the established star performers. Additionally, supergroups are often formed as side projects that are not intended to be permanent.   Wikipedia