Carrie Underwood has shared that her son has a new nickname for her, and it's reminding her of the days of her youth.

Underwood revealed in a humorous recent tweet the special name her 4-year-old son Isaiah referred to her as: "My own kid just called me 'Carefree Underwear.' This is basically elementary school all over again," she writes.

Many fans were quick to respond, sharing their own nickname stories. "Getting roasted by a toddler, great way to spend a Sunday if you ask me," writers one user. Meanwhile, another recalled attending an "Underwood Elementary" that her classmates amusingly renamed "Underwear Elementary."

Several others called little Isaiah a "ham" and said he could be a future comedian, and a fan in Canada revealed that her husband lovingly calls the singer "Carrie Underpantswood."

WOMAN Nashville suggested she turn the name into a new product for her workout wear line, Calia by Carrie; and another fan sweetly commented, "Enjoy those cute little memories from them! Ya can’t get them back!"

Underwood and husband Mike Fisher welcomed Isaiah's little brother Jacob on Jan. 21. She'll soon hit the road on her five-month Cry Pretty Tour 360 with Maddie & Tae and Runaway June, kicking off May 1 in Greensboro, N.C.

See Pictures of Carrie With Her Baby Boy!

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