In each episode of "Greatest Hits," comedian Arsenio Hall and country singer Kelsea Ballerini highlight a different five-year period of the 1980s, 1990s and 2000s, calling out the biggest hits from the era. Iconic music artists and current chart-toppers join the hosts in celebrating these moments in music by taking the stage for solo performances, special duets and tributes. Artists scheduled to make appearances during the six-week event include REO Speedwagon, Jason Derulo, and Kool & the Gang.