Kelly Clarkson Tackles New Radicals With Latest Cover, Talks 'Mean Celebs' During 'Idol' Days: Watch

"I have to say you're kind of like my good luck charm," Astin told Clarkson when she praised his cover, noting that he also did "Since U Been Gone" in the first PP movie and on the soundtrack.

But, he added, "I don't know if you know this, but your songs are hard!" Clarkson agreed, joking that she usually figures that out when she goes on tour and realizes she has to sing "all 17 of these songs every single night! Like over and over. That's when I lower the [register of the] songs."

Astin said his moment with Zoey was especially special because it's the first time that Levy's character has sung a duet with someone on the show.

In the same episode, Clarkson chatted with 9-1-1 star Jennifer Love Hewitt about the time the actress ran up to her on the red carpet at an MTV awards show when Clarkson was in the top three on the first season of Idol and provided a rare dose of kindness in a sea of bile. "People were like really mean to us because we're from a talent show and it was the first season," Clarkson said. "Everyone was so rude to us, on the carpet, at the show... it was so bad. It was a horrible experience." But JLH ran up to Clarkson and told her that she was "really rooting" for her while dropping some sage advice.

"'Please keep the ones you love so close and it will end up being about a few people in your life, unfortunately, but this business can be really hard and just remember to keep those people that really love you,'" J Love told her, advice that stuck with Clarkson to this day.

Check out the clips below.