Valentine's Day was extra sweet this year for Carrie Underwood, who received two adorable cards from her sons, seven-year-old Isaiah and four-year-old Jacob. The singer showed off her Valentine's Day love on social media, letting fans take a peek at how her two boys celebrated the holiday.

Underwood's older son was able to write out a message on his own, and also decorated a colorful heart card with rainbow stripes and the message "I <3 U" in the middle of the design.

"Dear Mom, you work so hard all the time," the card reads. "You are so loving when I am sick. I hope you have a happy Valentine's Day! Love, Isaiah."

"From my lil Valentine's," the singer commented below the snapshot, along with a string of red hearts.

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At only four years old, Jacob couldn't write out quite such an eloquent message of love for his mom on Valentine's Day, but he did get his sentiment across with a colorfully decorated heart card adorned with pink, gold and white crepe paper. "I love you to pieces," the card reads in print.

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The Underwood family is celebrating this Valentine's Day with an extra special, four-legged Valentine, too: The singer recently adopted a puppy named Charlie during a Denim & Rhinestones tour stop in Charlotte, N.C. She first announced that exciting news during her Charlotte show, and asked the crowd to keep the news a secret for a little bit, as she planned to surprise Isaiah and Jacob with the new addition to the family.

Underwood's Denim & Rhinestones Tour will continue into March.

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