'The Disney Holiday Singalong': Everything you need to know

Start your vocal warmups now: tonight, "Disney Holiday Singalong" will let you belt out your favorite holiday songs -- and a few Disney classics -- sung by some of your favorite musical stars.

The third installment of the "Disney Singalong" special features Katy Perry, Pink, opera legend Andrea Bocelli, K-pop superstars BTS and many more lending their famous voices to bring some holiday cheer to ABC viewers.

"So many people talked about the first two volumes of the show, that we felt like we had to do it again, and what a perfect time," host Ryan Seacrest said. "[And] a lot of the artists are on with their kids and their families, which makes it really special."

In addition to the pop stars, the show will feature the casts of Disney on Broadway shows including "Frozen," "The Lion King" and "Aladdin," who all gathered at Broadway's New Amsterdam Theater for what Seacrest called "the most amazing rendition of 'Let It Go' -- you have to see it!"

"Y'know, Broadway's been shut down since the beginning of spring and this is the first time that these performers will be onstage together [since then]," the "American Idol" host added, "which is remarkable."

As for the concept's popularity, Ryan explained: "I got so much great feedback from moms, dads, kids -- they got together in their living rooms and they sang together and they loved the fact that we provided them with the lyrics. I think that helps, so nobody can have the excuse of not participating."

"Except for me," he joked. "I can't sing, so I won't ... but I'll be watching you!"

The special will raise awareness of Disney's Feed the Love campaign, which supports the charities Feeding America, Toys for Tots and One Simple Wish.

"The Disney Holiday Singalong" airs at 8 p.m. ET on ABC. Here's a list of who's singing what:

Andrea Bocelli – "Silent Night"BTS – "Santa Claus Is Coming To Town"Michael Bublé – "It's Beginning to Look a Lot Like Christmas"Ciara – "Rockin' Around the Christmas Tree"Chloe x Halle – "Do You Want to Build a Snowman?"Derek Hough and Hayley Erbert – "Hey Santa" and "Jingle Bells"Julianne Hough – "Whistle While You Work" and "Let It Snow"Adam Lambert – "Have Yourself a Merry Little Christmas"Leslie Odom Jr. – "What's This?"Katy Perry – "I'll Be Home for Christmas" and "Cozy Little Christmas"Pink – "The Christmas Song (Chestnuts Roasting on an Open Fire)"Kerry Washington – "Joy to the World"

Disney is the parent company of ABC News and "Good Morning America."