AceShowbiz - Carrie Underwood's five-year-old son is "so proud" he's part of her first ever Christmas album, he's playing the sweet song to all his school pals.
"He's never been in that kind of situation before. I don't think he's even been like, in the studio with me ever before."
In fact, the "Love Wins" hitmaker isn't even sure Isaiah knows what his mother does for a living.
"I don't know if he knows what I do at all," she laughed, "but I could hear his voice on it (track) in my head when I was singing it in the studio and I just thought, 'Ask him and see if he might want to (sing on it).' "
And she needn't have worried if Isaiah would rise to the occasion because the star rated her child's performance as "great."
"He did such a great job," she added, "and... he's so proud of himself, he went to school and he said, 'Hey, my song's out. Wanna hear my song?' And they were listening to it in his class."
The album debuted at No. 8 on Billboard Hot 200 and hit the pinnacle on the Billboard Top Country Albums, marking Carrie's eighth consecutive No. 1 album on the Country chart. It also reigned the Top Christian Albums and Top Holiday Albums.