Carrie Underwood Says Son Isaiah 'Did Such a Great Job' Singing 'Little Drummer Boy'

Carrie Underwood's older son, 5-year-old Isaiah, was one of the guests featured on her recently-released holiday album, My Gift, joining his mom on "Little Drummer Boy." During an appearance on PEOPLE the TV Show, Underwood discussed working with her son on the song, sharing that Isaiah was so excited in the recording studio he was "throwing his hands up into the air."

"He did such a great job," she said. "He remembered the lyrics and he sang it with his whole heart." The Oklahoma native added that when she first heard the song with Isaiah's vocals on it, "I was laughing and crying at the same time because it was just this beautiful, pure moment from him."

Now that Isaiah is getting older, he has a better idea of what his famous mom does for a living, and Underwood said she can "see little lightbulbs coming on."

"It's mainly when other people talk about it to him," she noted. "If we'll be there with a little friend and the friend's mom is like, 'Oooh now this is Carrie Underwood.'"

While she's Carrie Underwood on stage, Underwood is just mom at home, making Halloween costumes for her kids like lots of other parents. In early October, the Grammy winner told RADIO.com's Katie & Company that Isaiah wanted to be Oogie Boogie from The Nightmare Before Christmas, though the singer was finding that the character's costume seemed to only be offered for adults.

"I'm having some trouble finding that costume, only because it's for adults," she said. "Lord help us if I have to make 'Ooogie Boogie.' So, we're gonna see. Maybe I'll get a potato sack-type of situation, a burlap sack. Maybe I can make one out of that, I'm not sure. Wish me luck!" As for the rest of the family's costumes, Underwood was also unsure. "I don't know what we're going to be for Halloween," she shared. "We've done the pumpkin carving thing... so we've got some decorations."

Underwood posted her own costume, a spooky ensemble that saw her don a white wig, veil and black lipstick, on her own Instagram Story, but she hasn't yet shared what Isaiah, her husband Mike Fisher or their younger son, 1-year-old Jacob, ended up wearing.