'America's Got Talent' Holiday Special: Heidi Klum Talks 'Santa Baby' Duet, Grace VanderWaal Previews 'Frosty'

America's Got Talent is ready to deck the halls with the premiere of the star-studded America’s Got Talent Holiday Spectacular 8 p.m. tonight (Dec. 19) on NBC.

The special has all the makings of a joyous family reunion, as host Nick Cannon and judges Mel B, Heidi Klum, Simon Cowell and Howie Mandel return for two hours of festive cheer and performances that aren't your run of the mill holiday fare.

Tonight's extravaganza features season 11 winner Grace VanderWaal (see a preview of her "Frosty the Snowman" below), along with fan favorites the Clairvoyants, Brian Justin Crum, Olate Dogs, Piff the Magic Dragon and special guests Penn & Teller and crooner Sal Valentinetti, who performs a festive “Santa Baby” with Klum. 

Additional performances will include season five singer Jackie Evancho, ninth-season winner Mat Franco, the Regurgitator and daredevil Professor Splash, who will perform a seasonally appropriate dive into a pool of eggnog.

Billboard caught up with Klum to talk about her forthcoming duet with Valentinetti, her own holiday plans and her thoughts on AGT season 12.

Your Golden Buzzer moment picking Sal was the most emotionally honest moment this summer. How proud are you of him? And what can you tell us about your duet with Sal? I'm not sure I have ever heard you sing!

I am so proud of him! He truly is one of a kind,and he is going to do big things in the future. The producers of AGT thought it would be fun for us to sing together for the holiday special, and I am always game to try! So we have a fun little number we're doing together. I'm excited to be able to get on stage with Sal. I love singing, but I'm not a singer like Sal! I'm hoping the other judges don't press their X buzzers on me!

The concept of an AGT Christmas special is fantastic, because it isn't all singing. The Clairvoyants, Regurgitator and Professor Splash diving into eggnog could create some wacky Christmas moments that deviate from the usual holiday fare. What inspired this unique decision?

This is what makes AGT so special -- it's a mix of people with all sorts of talents. We have amazing singers like Grace and Sal, but we also have people who do crazy stunts that makes the show so exciting. This is just like any other episode of AGT, you never know what the contestants will do next! 

Grace VanderWaal's new EP, Perfectly Imperfect, makes the perfect Christmas gift!  Have you heard any of it? We see she's going to do a cool Christmas cover tonight!

I actually just bought it the other day! I am still amazed at how a girl so young can have such a strong voice and presence on stage. It's like she's been doing this her entire career, but in reality it's only just begun! She is an extremely talented young woman and whatever she does I'm sure it will be amazing. 

Watch Grace VanderWaal Perform "Frosty the Snowman"

Can this special become a new holiday tradition? 

Why not? It's so much fun to get everyone back together and bring back past contestants. We're one big family, and who doesn't love a family holiday reunion?

Which alumni are you most excited to have back? 

The Regurgitator is a favorite of mine from season 10 who I am excited to see again. Every time I see him perform, I am always amazed by him! I can't give away all the surprises. You'll have to tune in to the special and see what we come up with! 

2016 is drawing to a close, but auditions for next year have already started. How on earth can you top last summer? The talent pool was so strong!

Yes, auditions for season 12 have started. It's hard to believe that we're already working on next season. It feels like we just had the season finale! Somehow the talent keeps getting better and better every year, so I'm excited to see who we have next season! 

What have you learned in the past several seasons on the panel? Did working with Simon Cowell or switching to Los Angeles change the way you judged? 

Over the years I've learned that you should always give your honest opinion, even if that means disagreeing with the other judges or getting booed by the audience! Everyone has their own thoughts on each performance and it's important to share those. Simon hasn't really changed the way I judge, but sometimes he does change my vote from a no to a yes. When there are singers on stage, Simon will have them sing a different song if he doesn't think the one they chose is the right song. He has an ear for that, so when they start singing that second song, I go, "Oh my gosh," he got something out of them that we didn't hear before. 

What are your holiday traditions or favorite Christmas songs?

I love the holidays! We decorate practically every inch of the house so it feels really festive. My kids love it. German tradition is to have the big dinner and celebration on Christmas Eve, so that's our special night.