S19E20 All About Lisa
Sideshow Mel recounts events leading up to Lisa getting the Entertainer of the Year award. Having berated Krusty for not engaging Bart as his sidekick she gets a job as the clown's personal assistant and gradually edges him out of the limelight as she substitutes for him when his misadventures render him unavailable. However Mel points out to her the pitfalls that come with fame. Bart meanwhile has taken up coin collecting with Homer,even cheating Burns out of ownership of the extremely rare 1917 Kissing Lincoln coin.