Carrie Underwood is not a morning person. In fact, the Christian country crooner has admitted that she's quite a grouch in the morning, but her mood instantly changes when she sees her newborn son Isaiah Michael Fisher.

"He's just this gift and such a smiley baby and so easy to be around," she told Taste of Country. "I'm a grouch in the morning and I wake up and he wakes up and he's just smiling at me. So he just makes my life better."

Underwood is so in love with her baby boy that he has become the inspiration for her new album.

She earlier revealed plans on writing songs about her son since all of the others she had written in the past had been centred on female relationships.

"I just kind of feel a little sad 'cause all my songs are about having girls," she joked to Unreality TV UK. "Like, little boy baby Fisher's got nothin'! Even 'Forever Changed,' which is one of my favourite songs, is definitely like a mother/daughter kind of a song, so... I'm gonna have to get on that."

Other songs Underwood wrote that are about daughters are "All-American Girl" and "Mama's Song," which she dedicated to her own mother right before she wed National Hockey League (NHL) player Mike Fisher.

Underwood first introduced her son to her fans with an Instagram post of his hand. "Tiny hands and tiny feet...God has blessed us with an amazing gift! Isaiah Michael Fisher - born on February 27. Welcome to the world, sweet angel!" she wrote on her Instagram account (@carrieunderwood).