“You and Willow have been bickering all morning, and I wouldn’t have it any other way,” the pop star wrote. “You bring so much light to the world, my boy. Thank you. Happy birthday.”
The post includes a few photos of Jameson over the years.
Hart also posted a birthday tribute to Jameson on Thursday.
“Happy 3rd b day to my lil Meatball!!! You are such an amazing kid, and I love you so much,” he wrote to accompany a slideshow of photos. “You are a constant crack up, and enjoy every moment with you. Enjoy your day lil man.”
"Yeah, we did 2 1/2 years, and Willow is back in school now, and Jameson's gonna start preschool soon, so it's kind of the year of the family," she told "Entertainment Tonight," with both of her children and her husband, Carey, by her side.
Pink also explained that she is taking a break to let her supportive husband focus on his career.
"Carey has a lot going on as well," she shared. "He is super supportive. He follows me around the world, and now it's his turn."
The two will celebrate their 14th anniversary on Jan. 7.