usually refers to any celebrity that has reached the highest point in their career, and eventually they'll screw up their lives and their reputations will be scarred.
ex.Britney Spears gone cahoots by shaving her head.
ex.MC Hammer was a big time superstar, now working in some mcdonalds in nowhere.
ex.Vanilla Ice(do i have to say any more?)
All examples of Burnout Superstars.