Old meets new on the ABC music series, Greatest Hits, premiering Thursday.
The network is bringing nostalgia back to primetime with the six-week event, featuring the biggest hitmakers of the past three decades, never-before-seen duets and incredible tributes like Jason Derulo singing Michael Jackson's 1983 hit, "Human Nature."
"It's kind of funny because a lot of the times when we're writing intros, her line is, 'And that was before I was born,'" Hall, 60, joked.
After this week's episode, which is all about the early '80s, next week tackles the '90s, where the Backstreet Boys reigned supreme. Meghan Trainor got to live out a childhood dream by doing a duet with the boy band.
"They're the nicest guys ever," the 22-year-old "All About That Bass" singer told ET. "They're goofballs and they make me feel really comfortable onstage and less nervous than I was this morning. It was like I was supposed to be in their band all along! I don't know what happened. I was born too late, you know?"
Greatest Hits debuts June 30 at 9 p.m. ET/PT on ABC.