Watch Carrie Underwood serenade son with helium voice for his birthday

Birthday boy! Carrie Underwoodserenaded her 4-year-old son, Isaiah, on his big day, but she sang the classic “Happy Birthday” song with a twist.

The country singer, 35, sucked from a yellow balloon before giving her son a dramatic rendition of the song in a video her husband, Mike Fisher, posted on Instagram on Wednesday, February 27. Underwood added extra syllables to Isaiah’s name, and as soon as she finished, the little one reached out for the balloon to try for himself.

The American Idol alum held her newborn baby boy in her arms while she performed. Jacob was born on January 21.

The “Cry Pretty” singer announced his birth on Instagram two days after he arrived, writing, “Jacob Bryan Fisher entered the world in the wee hours of the morning on Monday. His mom, dad and big brother couldn’t be happier for God to trust them with taking care of this little miracle! Our hearts are full, our eyes are tired and our lives are forever changed. Life is good.”

The former NHL player, 38, posted a close-up pic of their second son that same day. “Jacob Bryan Fisher! You are a gift from our Lord!” he wrote. “The last few years has has had its challenges and it makes this moment even more sweet!”

Fisher added: “We didn’t know if Izzy would ever have another sibling but we learned through it all that God is in control and his timing is perfect! He is good all the time even in the difficult times that are hard to understand. #grateful #miracle baby.”

The couple, who tied the knot in 2010, welcomed Isaiah in 2015. Underwood and Fisher’s eldest didn’t just celebrate his birthday with a high-pitched song this year, but went to a Nashville Predators hockey game on Tuesday, February 26, and stood on the ice with his dad.