Kirstin Maldonado and Mitch Grassi of Pentatonix, Adam Lambert, and Ledisi may all be big voices from mainstream music (Pentatonix and Ledisi are Grammy winners and Lambert a Grammy nominee), but turns out they’ve each been influenced by the music of Wicked. Which is why they’ve all been tapped to perform alongside Wicked’s original leading ladies Idina Menzel and Kristin Chenoweth in October 29’s concert special A Very Wicked Halloween, featuring the hit tunes from the Broadway show in celebration of its 15th anniversary.

“The second the soundtrack came out I feel like everyone was obsessed with it,” Maldonado tells Playbill in the video above. She and her four Pentatonix co-horts will be singing a new arrangement of a pivotal song in the show.

“It's a full circle moment, we grew up with this show and the [album] kind of shaped us as performers,” adds Grassi.

Ledisi is also a product of the musical theatre world, having worked on the out-of-town tryout of The Color Purple and understudying in the original Broadway production of Caroline, or Change. Now, she returns to the Broadway realm to sing “As Long As You're Mine” with recording artist and actor Lambert.

Though Lambert is best known for breaking out on American Idol, his music history entwines with that of Wicked. “Word on the street was there's this musical, it's amazing,” Lambert recalls. He auditioned and was cast as an ensemblist and Fiyero cover in the national tour of Wicked in 2005. He even went on for the role.

Tune in to watch Lambert step back into Fiyero’s boots, plus performances from Ariana Grande, Menzel, and Chenoweth on NBC.