Carrie Underwood shares son Isaiah's crush on Maddie Marlow

May 10 (UPI) -- Carrie Underwood says her son Isaiah has a crush on country singer Maddie Marlow.

The 36-year-old singer took to Twitter Thursday after Isaiah, her 4-year-old son with husband Mike Fisher, tried to impress Marlow.

Marlow, 22, and Taylor Dye make up the country music duo Maddie & Tae. The pair are opening for Underwood on her Cry Pretty 360 tour.

"This morning my 4-year-old, who hates wearing jeans, asked to wear jeans so he could 'look cute for Maddie.' He also asked me to fix his hair and to get him some flowers that he could give to her. Don't you break his heart @MaddieMarlow!!!" Underwood wrote, adding a tears of laughter emoji.

Marlow responded on Twitter, saying she was moved by Isaiah's gesture.

"I seriously could've cried. My heart just about exploded," she wrote. "Y'all raised the sweetest boy! Goes to show what a great example you and your hubby set for your boys. #newtourboyfriend."

Underwood is also mom to 3-month-old son Jacob Bryan, whom she gave birth to in January.

"His mom, dad and big brother couldn't be happier for God to trust them with taking care of this little miracle!" Underwood wrote on Instagram at the time. "Our hearts are full, our eyes are tired and our lives are forever changed. Life is good."

Underwood kicked off her Cry Pretty 360 tour May 1 and will next perform Saturday in Las Vegas. The tour is in support of her album Cry Pretty, which debuted in September.