Thomas Rhett honors daughter Willa on her 5th birthday: 'You make me such a better human being'

"You make me such a better human being," the country star wrote.

Thomas Rhett commemorated daughter Willa Gray's fifth birthday with a heartfelt letter.

On Sunday, the country superstar turned to Instagram to share his admiration for his eldest daughter, citing her as an "amazing" big sister to Ada James and Lennon Love, in addition to being wise beyond her years.

"WG you continue to amaze me with your heart, your kindness, your selflessness, and your hilariousness. You make me such a better human being, and I’m inspired by you every single day. You may be 5 but you already act like your 15," Rhett wrote. The post is accompanied by a slideshow of photos of Willa through the years, including one of her sitting on her dad's lap as a toddler and another flashing her beautiful smile at the camera with a crystal blue body of water in the background.

"I can’t wait to watch you grow and be there with you every step of the way. To my beautiful baby girl, happy birthday sweet pea!" he concluded.

Rhett's wife, Lauren Akins, also used Instagram to express her gratitude for her daughter, whom she met while on a service trip in Uganda. Akins also reiterated Willa's selflessness and said the 5-year-old is "the easiest person to celebrate."

"Willa Gray I say this all the time but I mean it: you are full of magic baby!" she wrote. "I’m so happy our souls found each other because I wouldn’t be complete without you. Happy birthday precious girl."

The couple brought Willa home from Uganda in 2017 after a year-long adoption process. That same year, they welcomed their second daughter, Ada, followed by Lennon in 2020.