Carrie Underwood, Son, Isaiah, Jacob

Instagram / Mike Fisher

None of us will ever sound this good on helium...

Carrie Underwood's husband Mike Fisher posted on his Instagram page on Wednesday night a hilarious video of her singing "Happy birthday" to their eldest son Isaiah Michael Fisher, 4, after inhaling from a yellow birthday balloon filled with helium.

The 35-year-old Grammy-winning singer serenaded the boy, who looked highly amused, while holding his 1-month-old baby brotherJacob Bryan Fisher.

"Happy birthday Isaiah!!" Mike wrote.

This weekend, Carrie and her family celebrated Isaiah's birthday early with a Muppets-themed birthday cake.

"Ummm... @iveychildersand @iveycakestore have outdone themselves once again! Isaiah loves the Muppets and his favorite movie right now is Muppets Most Wanted," Carrie wrote on Instagram, alongside a photo slideshow.

"He wanted a 'most dangerous frog' cake and he most certainly got one! And it tasted as delicious as it looked!" she added. "Thanks for making his birthday celebration extra special! #MyBestieIsABaker #IveyCake #Yum."

Happy birthday, Isaiah!

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