Michael Bublé kicked off the show surrounded by his family while singing "It's Beginning to Look a Lot Like Christmas" while previews of what was to come appeared on the ornaments hanging on the tree behind him. Next up, "Hollywood's hottest couple" Kermit and Miss Piggy delivered a vocal warm-up of sorts that ended in Piggy's soaring notes cracking the camera lens. But Seacrest made it clear you don't have to have a perfect voice to join in on the fun: "We're celebrating all the holidays," he said. "Wherever you are in the world" -- from South Korea to Italy to Los Angeles -- "this singalong is for you."
Here are seven highlights from the holiday special:
Chloe x Halle: "Do You Want to Build a Snowman?"
"It's time for one of life's great questions: Do you want to build a snowman?" asked Seacrest before introducing a "pair of talented sisters, just like [Frozen's] heroines." For Chloe x Halle's performance, the sisters once again transformed their backyard to create a stunning at-home set overflowing with decorated trees and even some light snow falling from the sky. Plus, their performance wouldn't be complete with their own version of Olaf. And as the sisters belted out beautifully chilling harmonies, they wrapped a scarf around their snowball friend.
BTS: “Santa Claus Is Coming To Town”
Joining the singalong from Seoul, the K-pop superstars introduced the Christmas classic by channeling the man himself, chuckling "ho ho ho" as they walked onto the present-filled set dressed in cozy sweaters and scarves. Halfway through, RM gave his best Santa impression while asking viewers: “What do you wish for this Christmas? BTS!” He later delivered a sky-high note before the group wished everyone a happy holiday.
Ciara: "Rockin' Around the Christmas Tree"
Following a heart-warming performance from P!nk and her 9-year-old daughter Willow, Seacrest teased Ciara's clip by telling fans the show was going "from one talented mother to another.” He then joked that her kids, Future and Sienna, were trying to take his job as they introduced their mom's song of choice. And that wasn't all they did -- they also joined in on the fun, dancing and singing along with their mom. While Ciara and Sienna wore matching vintage '50s varsity jackets, Future sported a leather jacket and aviators to drive home the vintage-inspired visual.
Disney on Broadway: "Let It Go"
While the Disney on Broadway cast members have participated in the previous two Disney Singalongs, this one was particularly special: It was their first time performing onstage -- and together -- since Broadway's shutdown in the spring. The members joined forces at Times Square's New Amsterdam Theatre for the Frozen hit, and when they sang the line "We’re never going back … the past is in the past," it hit unintentionally hard.
Leslie Odom Jr.: "What’s This?"
The Hamilton star delivered an impassioned and incredibly speedy delivery of The Nightmare Before Christmas track, mirroring Jack Skellington's movements from the film that played behind him. Prior to his performance, Odom admitted to Seacrest he was a bit nervous, but after he was seen smiling in front of the at-home green screen -- and standing next to a Jack Skellington-inspired snowman -- it was clear he knew he nailed it.
Katy Perry: "I’ll Be Home for Christmas / Cozy Little Christmas"
Seacrest said it best when he introduced Katy Perry's performance by saying she "put her heart and soul -- as we’ve come to expect" into her clip, "really going the extra mile" (for those who don't remember, Perry dressed as Mrs. Jumbo for her last Disney Singalong performance). And somehow, even that was an understatement. Perry started her performance of not one but two Christmas songs strapped atop a moving vehicle because, of course, she was dressed as a Christmas tree. After fighting to be taken down, Perry the tree was then shown inside a family's home all dressed up with ornaments and lights while being fed pie in between verses. As Seacrest said: “I've never been more moved by a singing tree."
Adam Lambert: "Have Yourself a Merry Little Christmas"
Adam Lambert had the highly sought-after closing slot, which appeared just before the legendary Andrea Bocelli wrapped the special as at-home fan videos aired. But to no one's surprise, Lambert over-delivered by adopting the less-is-more strategy, opting for gorgeous sky-high notes rather than costumes or green screens. Seated in his backyard, he performed what Seacrest said was "Minnie Mouse's personal favorite" and balanced soft, tender moments with unparalleled vocal strength.