Carrie Underwood celebrates son Isaiah's birthday with tribute, pic of 'epic' cake

Carrie Underwood showered her oldest son, Isaiah, with love on his sixth birthday.

The country music superstar, 37, posted two pics to Instagram on Saturday in celebration of Isaiah's big day. One photo showed off his awesome "Power Rangers"-themed birthday cake, and the second was a black-and-white image capturing the mother and child in a sweet embrace.

"Today, we celebrate Isaiah... because today, he is 6 whole years old! Isaiah, you are kind, funny, smart, the best big brother, a lover of cuddles and crafts and you have the biggest heart and the best imagination!" she gushed.

"You love to make people feel good and you especially love to make them laugh! God has given you so many gifts and every day, I thank Him that I get to be your mom! I love you, Monkey! Happy birthday!" she added.

Underwood, who shares Isaiah and younger son Jacob, 2, with her husband, former NHL pro Mike Fisher, also thanked the Ivey Cake shop in Brentwood, Tennessee, "for this epic Power Rangers cake!!! Yum!!!"

Fisher, 40, shared Underwood's second image on his own Instagram page, writing, "Happy 6th birthday Isaiah! I’m blessed to be your dad and proud of how you love Jesus and others so well! And please stop growing up so fast!!"

Isaiah may be only in grade school, but he's already made his musical debut. The talented youngster helped his mom sing her rendition of "Little Drummer Boy" on her 2020 holiday album, "My Gift."

Having Isaiah join her on the song made sense given Isaiah's generous nature.

“Whenever I think about that song, I picture (Isaiah's) face and personality — that is so him. He would be the kid that would make you something and bring it to you, because that’s what he had to give you. That’s the whole sentiment behind 'Little Drummer Boy,'" Underwood told TODAY’s Savannah Guthrie last September.

The former "American Idol" champ admitted that spending time in the studio with Isaiah brought out her inner stage mom.

"I was in the booth with him and trying to get him to access all of his little 5-year-old emotions, which he can totally do on his own. ... He was just so expressive! When I heard the song back, with his sweet little voice on it, I was laughing and crying and just so many emotions," she shared.

Of course, Isaiah's not the only special little guy in Underwood's life.

The singer posted a loving birthday tribute to her younger son when he turned 2 in January.

“Jacob, we longed for you. We prayed for you. We walked a long, hard road in order to one day hold you,” she wrote next to a baby pic of Jacob she shared on Instagram.

“Today you are two. You are silly and strong. You love to play and sing and follow your big brother around. You are loved. You are cherished. You are an incredible blessing from God. Happy birthday, sweet boy!” she added.