The 36-year-old country crooner took to Instagram over the weekend to share a hilarious video of some family time she had with her husband, Mike Fisher, and their youngest son, 5-month-old Jacob.
In the clip, the couple, who also share 4-year-old Isaiah, take turns singing Vince Gill's "I Still Believe In You" to mixed reviews from little Jacob.
Fisher, the 39-year-old former NHL player, starts out singing the sweet track while standing over his son, who is screaming crying. When Underwood, who's heard off camera, takes over singing duties after a few lines, Jacob immediately quiets down and snaps his head over to look at his mom.
The whole thing repeats a couple of times with sobs from Jacob during Fisher's singing parts and sheer contentment from the baby when Underwood takes over the tune.
"Everyone’s a critic...?♀️ @mfisher1212 @vincegillofficial ?," Underwood quipped in the caption.
Fisher didn't have quite the same takeaway from his son's reaction, commenting, "The real reason is he was hungry and wanted your food. #notmysinging ??"
Fellow celebs couldn't get enough of the clip, with Justin Timberlake chiming in to dub the video "the greatest thing I've seen all year."
Country star Brad Paisley's wife, Kimberly Williams Paisley, also praised the clip, writing, "Oh my gosh I’m dying ?????"
ET's Nischelle Turner caught up with the "Cry Pretty" singer earlier this month, and she gushed about her adorable little boys.
"My 4-month-old is just four months of squishiness and smiley," she said of Jacob. "And I love those smiley babies."
As for Isaiah, Underwood called her oldest son "a schmoozer."
"He knows the right things to say and he's so cute about it and he knows how to get, not get what he wants but a little bit," she shared. "And he'll totally [work it], especially with girls he's so sweet."